Anemia

Anemia (dalam bahasa Yunani: Tanpa darah) adalah keadaan saat jumlah sel darah merah atau jumlah hemoglobin (protein pembawa oksigen) dalam sel darah merah berada di bawah normal.
Sel darah merah mengandung hemoglobin yang memungkinkan mereka mengangkut oksigen dari paru-paru, dan mengantarkannya ke seluruh bagian tubuh.
Anemia menyebabkan berkurangnya jumlah sel darah merah atau jumlah hemoglobin dalam sel darah merah, sehingga darah tidak dapat mengangkut oksigen dalam jumlah sesuai yang diperlukan tubuh .
Penyebab Anemia
Penyebab umum dari anemia:

 Gejala

Gejala-gejala yang disebabkan oleh pasokan oksigen yang tidak mencukupi kebutuhan ini, bervariasi. Anemia bisa menyebabkan kelelahan, kelemahan, kurang tenaga dan kepala terasa melayang. Jika anemia bertambah berat, bisa menyebabkan stroke atau serangan jantung.

Diagnosa

Pemeriksaan darah sederhana bisa menentukan adanya anemia. Persentase sel darah merah dalam volume darah total (hematokrit) dan jumlah hemoglobin dalam suatu contoh darah bisa ditentukan. Pemeriksaan tersebut merupakan bagian dari hitung jenis darah komplit (CBC).

Referensi : http://id.wikipedia.org/wiki/Anemia

Transudat dan Eksudat

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Transudat dan Eksudat

PEMERIKSAAN
A.      MAKROSKOPIS
·         Volume
Volume cairan diukur dengan menggunakan gelas ukur dan dilihat secara visual.
Harga normal : tidak ada/negative.
·         Warna
1.       Masukkan cairan kedalam tabung reaksi panjang.
2.       Amati warna cairan dengan mata secara visual.
3.       Harga normal :
Transudat : kuning muda.
Eksudat : tergantung penyebabnya.
                        Hijau: bilirubun / ikterus.
                        Merah : darah
                        Putih kekuningan : pus.
                        Putih spt susu : chyles.
                        Biru kehijauan : bakteri pyocyanus.
·         Kejernihan
1.       Masukkan sampel kedalam tabung reaksi panjang.
2.       Kejernihan dilihat dengan mata secara visual.
3.       Harga normal :
Transudat : jernih dan encer.
Eksudat : keruh dan kental.
·         Bau
1.       Masukkan sampel kedalam becker glass.
2.       Dekatkan ke hidung dan kibaskan tangan kearah hidung.
3.       Harga normal :
Transudat dan Eksudat : (-)
·         Bekuan
1.       Masukkan cairan kedalam becker glass.
2.       Dilihat adanya bekuan dalam cairan.
3.       Adanya bekuan dinyatakan dengan :
Renggang, berkeping, berbutir, sangat halus.
4.       Harga normal :
Transudat : (-)
Eksudat : (+)
·         Berat jenis
1.       Masukkan cairan kedalam gelas ukur 50 ml.
2.       Masukkan urinometer dan putar tangkai urinometer.
3.       Berat jenis dibaca pada tangkai urinometer setinggi miniskus bawah.
4.       Harga normal :
Transudat : 1006 -1015
Eksudat : 1018 - 1030
B.      KIMIA
·         Metode Rivalta
1.       Masukkan 100 ml aquadest ke dalam becker glass 250 ml.
2.       Tambahkan 1 tetes cairan asam asetat pekat,aduk dengan batang pengaduk.
3.       Tambahkan 1 tetes cairan yang diperiksa dengan jarak  1 cm diatas permukaan cairan.
4.       Perhatikan dangan latar belakang hitam.
5.       Harga :
a.       Cairan normal : (-) cairan bercampur dan bereaksi tanpa membentuk kekeruhan.
b.      Transudat : (+) lemah= cairan bercampur dan bereaksi membentuk kekeruhan ringan / kabut tipis.
c.       Eksudat : (+) kuat=  cairan bercampur dan bereaksi membentuk kekeruhan berat.
C.      PEMBAHASAN
Ø  Transudat terjadi sebagai akibat dari proses bukan radang oleh gangguan kesetimbangan cairan badan (tekanan osmotik koloid,stasis dalam kapiler atau tekanan hidrostatik, kerusakam endotel,dsb), sedangkan eksudat bertalian dengan salah satu proses peradangan.
Ø  Ciri-ciri transudat spesifik ; cairan jernih, encer, kuning muda, berat jenis mendekati 1010 atau setidaknya kurang dari 1018, tidak menyusun bekuan, kadar protein kurang dari 2,5 g/dl, kadar glukosa kira-kira sama seperti dalam plasma darah, jumlah sel kecil dan bersifat steril.
Ø  Ciri-ciri eksudat spesifik ; keruh, lebih kental, warna bermacam-macam, bj lebih dari 1018, sering ada bekuan, kadar protein 4,0 g/dl, kadar glukosa jauh kuran dari kadar plasma darah, mengandung banyak sel dan sering ada bakteri.

Golongan Darah

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Golongan darah



Dari Wikipedia bahasa Indonesia, ensiklopedia bebas

Golongan darah adalah ciri khusus darah dari suatu individu karena adanya perbedaan jenis karbohidrat dan protein pada permukaan membran sel darah merah. Dua jenis penggolongan darah yang paling penting adalah penggolongan ABO dan Rhesus (faktor Rh). Di dunia ini sebenarnya dikenal sekitar 46 jenis antigen selain antigen ABO dan Rh, hanya saja lebih jarang dijumpai. Transfusi darah dari golongan yang tidak kompatibel dapat menyebabkan reaksi transfusi imunologis yang berakibat anemia hemolisis, gagal ginjal, syok, dan kematian.
Golongan darah manusia ditentukan berdasarkan jenis antigen dan antibodi yang terkandung dalam darahnya, sebagai berikut:
  • Individu dengan golongan darah A memiliki sel darah merah dengan antigen A di permukaan membran selnya dan menghasilkan antibodi terhadap antigen B dalam serum darahnya. Sehingga, orang dengan golongan darah A-negatif hanya dapat menerima darah dari orang dengan golongan darah A-negatif atau O-negatif.
  • Individu dengan golongan darah B memiliki antigen B pada permukaan sel darah merahnya dan menghasilkan antibodi terhadap antigen A dalam serum darahnya. Sehingga, orang dengan golongan darah B-negatif hanya dapat menerima darah dari orang dengan dolongan darah B-negatif atau O-negatif
  • Individu dengan golongan darah AB memiliki sel darah merah dengan antigen A dan B serta tidak menghasilkan antibodi terhadap antigen A maupun B. Sehingga, orang dengan golongan darah AB-positif dapat menerima darah dari orang dengan golongan darah ABO apapun dan disebut resipien universal. Namun, orang dengan golongan darah AB-positif tidak dapat mendonorkan darah kecuali pada sesama AB-positif.
  • Individu dengan golongan darah O memiliki sel darah tanpa antigen, tapi memproduksi antibodi terhadap antigen A dan B. Sehingga, orang dengan golongan darah O-negatif dapat mendonorkan darahnya kepada orang dengan golongan darah ABO apapun dan disebut donor universal. Namun, orang dengan golongan darah O-negatif hanya dapat menerima darah dari sesama O-negatif.
Secara umum, golongan darah O adalah yang paling umum dijumpai di dunia, meskipun di beberapa negara seperti Swedia dan Norwegia, golongan darah A lebih dominan. Antigen A lebih umum dijumpai dibanding antigen B. Karena golongan darah AB memerlukan keberadaan dua antigen, A dan B, golongan darah ini adalah jenis yang paling jarang dijumpai di dunia.
Ilmuwan Austria, Karl Landsteiner, memperoleh penghargaan Nobel dalam bidang Fisiologi dan Kedokteran pada tahun 1930 untuk jasanya menemukan cara penggolongan darah ABO.

Penyakit Cacing

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Permasalahan Penyakit Cacing Pada Anak

Waspadai dan kenali penyakit cacing pada anak. Penyakit yang sering terjadi ini sangat menganggu tumbuh kembang anak. Sehingga sangat penting untuk mengenali dan mencegah penyakit cacing pada anak sejak dini. Gagguan yan ditimbulkan mulai dari yang ringan tanpa gejala hingga sampai yang berat bahkan sampai mengancam jiwa. Secara umum gangguan nutrisi atau anmeia dapat terjadi pada penderita. Hal ini secara tidak langsung akan mengakibatkan gangguan kecerdasan pada anak.
Sekitar 60 persen orang Indonesia mengalami infeksi cacing. Kelompok umur terbanyak adalah pada usia 5-14 tahun. Angka prevalensi 60 persen itu, 21 persen di antaranya menyerang anak usia SD dan rata-rata kandungan cacing per orang enam ekor. Data tersebut diperoleh melalui survei dan penelitian yang dilakukan di beberapa provinsi pada tahun 2006. Hasil penelitian sebelumnya (2002-2003), pada 40 SD di 10 provinsi menunjukkan prevalensi antara 2,2 persen hingga 96,3 persen. Sekitar 220 juta penduduk Indonesia cacingan, dengan kerugian lebih dari Rp 500 miliar atau setara dengan 20 juta liter darah per tahun. Penderita tersebar di seluruh daerah, baik di pedesaan maupun perkotaan. Karena itu, cacingan masih menjadi masalah kesehatan mendasar di negeri ini.
Cara Penularan

Cacing masuk ke dalam tubuh manusia lewat makanan atau minuman yang tercemar telur-telur cacing. Umumnya, cacing perut memilih tinggal di usus halus yang banyak berisi makanan. Meski ada juga yang tinggal di usus besar. Penularan penyakit cacing dapat lewat berbagai cara, telur cacing bisa masuk dan tinggal dalam tubuh manusia. Ia bisa masuk lewat makanan atau minuman yang dimasak menggunakan air yang tercemar. Jika air yang telah tercemar itu dipakai untuk menyirami tanaman, telur-telur itu naik ke darat. Begitu air mengering, mereka menempel pada butiran debu. Telur yang menumpang pada debu itu bisa menempel pada makanan dan minuman yang dijajakan di pinggir jalan atau terbang ke tempat-tempat yang sering dipegang manusia. Mereka juga bisa berpindah dari satu tangan ke tangan lain. Setelah masuk ke dalam usus manusia, cacing akan berkembang biak, membentuk koloni dan menyerap habis sari-sari makanan. Cacing mencuri zat gizi, termasuk protein untuk membangun otak.
Setiap satu cacing gelang memakan 0,14 gram karbohidrat dan 0,035 protein per hari. Cacing cambuk menghabiskan 0,005 milimeter darah per hari dan cacing tambang minum 0,2 milimeter darah per hari. Kalau jumlahnya ratusan, berapa besar kehilangan zat gizi dan darah yang digeogotinya. Seekor cacing gelang betina dewasa bisa menghasilkan 200.000 telur setiap hari. Bila di dalam perut ada tiga ekor saja, dalam sehari mereka sanggup memproduksi 600.000 telur.
Gejala dan Tanda

  • Pada kasus infeksi cacing ringan, tanpa gejala atau kadang tidak menimbulkan gejala nyata. Gejala lan yang harus dikenali adalah lesu, tak bergairah, suka mengantuk, badan kurus meski porsi makan melimpah, serta suka menggaruk-garuk anusnya saat tidur karena bisa jadi itu pertanda cacing kremi sedang beraksi.  Gangguan ini menyebabkan, kurang zat gizi, kurang darah atau anemia. Berkurangnya zat gizi maupun darah, keduanya berdampak pada tingkat kecerdasan, selain berujung anemia.  Anemia akan menurunkan prestasi belajar dan produktivitas. Menurut penelitian, anak yang kehilangan protein akibat cacing tingkat kecerdasannya bisa menurun.  Anemia kronis bisa mengganggu daya tahan tubuh anak usia di bawah lima tahun (balita).
  • Tetapi pada kasus-kasus infeksi berat bisa berakibat fatal. Ascaris pada cacing dapat bermigrasi ke organ lain yang menyebabkan peritonitis, akibat perforasi usus dan ileus obstruksi akibat bolus yang dapat berakhir dengan kematian.
  • Infeksi usus akibat cacingan, juga berakibat  menurunnya status gizi penderita yang menyebabkan daya tahan tubuh menurun, sehingga memudahkan terjadinya infeksi penyakit lain, termasuk HIV/AIDS, Tuberkulosis dan Malaria. Jenis penyakit parasit ini kecil sekali perhatiannya dari pemerintah bila dibandingkan dengan HIV/AIDS yang menyedot anggaran cukup besar, padahal semua bentuk penyakit sama pentingnya dan sikap masyarakat sendiri juga tak peduli terhadap penyakit jenis ini.

Beberapa Jenis Cacing

Beberapa jenis cacing sangat potensial untuk menimbulkan infeksi pada anak-anak. Dan untuk selanjutnya mereka akan menjadi sumber penularan bagi infeksi berikutnya yang sangat potensial. Keadaan yang demikian inilah yang menyebabkan infeksi akibat parasit cacing sukar diatasi secara tuntas. Penderita yang tidak mendapatkan pengobatan yang tepat, merupakan sumber penularan bagi orang-orang dekat di sekitarnya

  • Cacing gelang.  Cacing betinanya yang panjangnya kira-¬kira 20-30 cm ini mampu bertelur 200.000 telur per harinya. Dalam waktu lebih kurang 3 minggu telur ini akan berisi larva yang bersifat infektif, yang dapat menjadi sumber penularan jika secara tidak sengaja mencemari makanan/minuman yang kita konsumsi. Cacing ini hidup sebagai parasit dalam usus halus, sehingga akan mengambil nutrisi yang bermanfaat bagi tubuh kita dan menimbulkan kerusakan pada` lapisan usus tersebut. Akhirnya timbullah diare dan gangguan penyerapan sari-sari makanan tersebut. Bahkan pada keadaan yang berat, larva dapat masuk ke paru sehingga membutuhkan tindakan operatif.
  • Cacing cambuk (Trichuris trichiura). Cacing ini juga menghisap sari makanan yang kita makan. Dia menghisap darah dan hidup di dalam usus besar. Cacing betinanya bisa bertelur 5 ribu-10 ribu butir per hari. Biasanya infeksi cacing ini menyerang pada usus besar. Infeksinya sering menimbulkan perlakaan usus, karena kepala cacing dimasukkan ke dalam permukaan usus penderita. Pada infeksi yang ringan biasanya hanya timbul diare saja. Tetapi pada infeksi yang berat, hampir pada sebagian besar permukaan usus besar dapat ditemukan cacing jenis ini. Akibatnya diare yang terjadi juga relatif berat dan dapat berlangsung terus menerus. Karena juga dapat menyebabkan perlukaan usus, maka anemia sebagai komplikasi perdarahan merupakan akibat yang tidak begitu saja dapat dianggap ringan. Inilah sebetulnya akibat-akibat infeksi cacing yang tidak pernah kita perkirakan selama ini dan proses yang merugikan itu berlangsung terus tanpa kita sadari. Infeksi cacing biasanya menimbulkan anemia.
  • Cacing tambang (Necator americanus dan Ancylostoma duodenale). Inilah cacing yang paling ganas, karena ia menghisap darah. Cacing betinanya bisa bertelur 15 ribu-20 ribu butir per hari. Penularannya cepat, karena larva cacing tambang sanggup menembus kulit kaki dan selajutnya terbawa oleh pembuluh darah ke dalam usus. Cacing dewasa bertahan hidup 2-10 tahun. Cacing tambang ini menimbulkan perlukaan pada permu-kaan usus, sehingga perdarahan dapat terjadi secara lebih berat dibanding dengan infeksi cacing jenis lainnya. Perdarahan yang lebih berat ini disebabkan karena mulut (stoma) cacing mengerat permukaan usus. Bahkan satu ekor cacing saja dapat menyebabkan kehilangan darah sebanyak 0,005¬0,34 cc sehari. Mengingat itu semua, maka infeksi cacing tambang merupakan penyebab anemia yang paling sering ditemukan pada anak-anak, sehingga dapat mempengaruhi daya tahan tubuhnya dan menurunkan prestasi belajarnya. Telur cacing gelang yang masuk ke pencernaan akan menetas menjadi larva. Larva ini menembus dinding usus halus menuju jantung dan paru-paru. Cacing gelang menyebabkan gizi buruk dan membuat anak tidak nafsu makan, karena nutrisinya direbut cacing. Cacing betinanya bisa bertelur mencapai 200 ribu butir per hari. Cacing dewasa dapat bertahan hidup 6-12 bulan.
  • Cacing kremi. Cacing ini mirip kelapa parut, kecil-kecil dan berwarna putih. Awalnya, cacing ini akan bersarang di usus besar. Saat dewasa, cacing kremi betina akan pindah ke anus untuk bertelur. Telur-telur ini yang menimbulkan rasa gatal.  Bila balita menggaruk anus yang gatal, telur akan pecah dan larva masuk ke dalam dubur. Saat digaruk, telur-telur ini bersembunyi di jari dan kuku, sebagian lagi menempel di sprei, bantal atau pakaian. Lewat kontak langsung, telur cacing menular ke orang lain. Lalu siklus cacing dimulai lagi.
Pencegahan Penyakit Cacing Pada Anak
Untuk dapat mengatasi infeksi cacing secara tuntas, maka upaya pencegahan dan terapi merupakan usaha yang sangat bijaksana dalam memutus siklus penyebaran infeksinya. Pemberian obat anti cacing secara berkala setiap 6 bulan dapat pula dikerjakan. Menjaga kebersihan diri (Ian lingkungan serta sumber bahan pangan adalah merupakan sebagian dari usaha pencegahan untuk menghindari dari infeksi cacing. Memasyarakatkan cara-cara hidup sehat, terutama pada anak-anak usia sekolah dasar, dimana usia ini merupakan usia yang sangat peka untuk menanamkan dan memperkenal¬kan kebiasaan-kebiasaan baru. Kebiasaan untuk melakukan pemeriksaan kesehatan secara berkala merupakan salah satu contohnya.
Beberapa Tips Pencegahan :
  • Cucilah tangan sebelum makan.
  • Budayakan kebiasaan dan perilaku pada diri sendiri, anak dan keluarga untuk mencuci tangan sebelum makan. Kebiasaan akan terpupuk dengan baik apabila orangtua meneladani. Dengan mencuci tangan makan akan mengeliminir masuknya telur cacing ke mulut sebagai jalan masuk pertama ke tempat berkembang biak cacing di perut kita.
  • Pakailah alas kaki jika menginjak tanah. Jenis cacing ada macamnya. Cara masuknya pun beragam macam, salah satunya adalah cacing tambang (Necator americanus ataupun Ankylostoma duodenale). Kedua jenis cacing ini masuk melalui larva cacing yang menembus kulit di kaki, yang kemudian jalan-jalan sampai ke usus melalui trayek saluran getah bening. Kejadian ini sering disebut sebagai Cutaneus Larva Migran (dari namanya ini kita sudah tahu lah apa artinya; cutaneus: kulit, larva: larva, migrant: berpindah). Nah, setelah larva cacing sampai ke usus, larva ini tumbuh dewasa dan terus berkembang biak dan menghisap darah manusia. Oleh sebab itu Anda akan anemia. *Lha wong berbagi darah dan hidup dengan cacing
  • Gunting dan bersihkan kuku secara teratur. Kadang telur cacing yang terselip di antara kuku Anda dan selamat masuk ke usus Anda dan mendirikan koloni di sana.
  • Jangan buang air besar sembarangan dan cuci tangan saat membasuh. Setiap kotoran baiknya dikelola dengan baik, termasuk kotoran manusia. Di negara kita masih banyak warga yang memanfaatkan sungai untuk buang hajat. Dengan perilaku ini maka kotoran-kotoran ini akan liar tidak terjaga, sehingga mencemari lingkungannya. Dan, jika lingkungan sudah cemar, penularan sering tidak pandang bulu. Orang yang sudah menjaga diri sebersih mungkin sekalipun masih dapat dihinggapi parasit cacing ini.
  • Bertanam atau Berkebunlah dengan baik. Ambillah air yang masih baik untuk menyiram tanaman. Agar air ini senantiasa baik maka usahakan lingkungan sebaik mungkin. Menjaga alam ini termasuk bagian dalam merawat kesehatan.⁠
  • Peduli lah dengan lingkungan, maka akan dapat memanfaatkan hasil yang baik. Jika air yang digunakan terkontaminasi dengan tinja manusia, bukan tidak mungkin telur cacing bertahan pada kelopak-kelopak tanaman yang ditanam dan terbawa hingga ke meja makan.
  • Cucilah sayur dengan baik sebelum diolah. Cucilah sayur di bawah air yang mengalir. Mengapa demikian? Ya, agar kotoran yang melekat akan terbawa air yang mengalir, di samping itu nilai gizi sayuran tidak hilang jika dicuci di bawah air yang mengalir. Cara mengolah sayuran yang baik dapat Anda lihat di artikel Cerdas mengolah Sayuran : Menjamin Ketersediaan Nutrisi.
  • Hati-hatilah makan makanan mentah atau setengah matang, terutama di daerah yang sanitasinya buruk. Perlu dicermati juga, makanan mentah tidak selamanya buruk. Yang harus diperhatikan adalah kebersihan bahan makanan agar makanan dapat kita makan sesegar mungkin sehingga enzim yang terkandung dalam makanan dapat kita rasakan manfaatnya. Ulasan saya tentang makanan mentah yang menyehatkan dapat dilihat pada artikel Diet Sunda ini.
  • Buanglah kotoran hewan hewan peliharaan kesayangan Anda seperti kucing atau anjing pada tempat pembuangan khusus
  • Pencegahan dengan meminum obat anti cacing setiap 6 bulan, terutama bagi Anda yang risiko tinggi terkena infestasi cacing ini, seperti petani, anak-anak yang sering bermain pasir, pekerja kebun, dan pekerja tambang (orang-orang yang terlalu sering berhubungan dengan tanah.
Pengobatan
  • Penanganan untuk mengatasi infeksi cacing dengan obat-obatan merupakan pilihan yang dianjurkan. Obat anti cacing Golongan Pirantel Pamoat (Combantrin dan lain-lain) merupakan anti cacing yang efektif untuk mengatasi sebagian besar infeksi yang disebabkan parasit cacing.
  • Intervensi berupa pemberian obat cacing ( obat pirantel pamoat 10 mg / kg BB dan albendazole 10 mg/kg BB ) dosis tunggal diberikan tiap 6 bulan pada anak SD dapay mengurangi angka kejadian infeksi ini pada suatu daerah
  • Paduan yang serasi antara upaya prevensi dan terapi akan memberikan tingkat keberhasilan yang memuaskan, sehingga infeksi cacing secara perlahan dapat diatasi secara maksimal, tuntas dan paripurna
Referensi:
http://clinicforchild.wordpress.com/2012/01/29/permasalahan-penyakit-cacing-pada-anak/

Pseudomonas aeroginusa

Label:

Pseudomonas aeruginosa



From Wikipedia, the free encyclopedia

Pseudomonas aeruginosa
P. aeruginosa on an XLD agar plate
Scientific classification
Kingdom:Bacteria
Phylum:Proteobacteria
Class:Gamma Proteobacteria
Order:Pseudomonadales
Family:Pseudomonadaceae
Genus:Pseudomonas
Species:P. aeruginosa
Pseudomonas aeruginosa is a common bacterium that can cause disease in animals, including humans. It is found in soil, water, skin flora, and most man-made environments throughout the world. It thrives not only in normal atmospheres, but also in hypoxic atmospheres, and has, thus, colonized many natural and artificial environments. It uses a wide range of organic material for food; in animals, the versatility enables the organism to infect damaged tissues or those with reduced immunity. The symptoms of such infections are generalized inflammation and sepsis. If such colonizations occur in critical body organs, such as the lungs, the urinary tract, and kidneys, the results can be fatal. Because it thrives on most surfaces, this bacterium is also found on and in medical equipment, including catheters, causing cross-infections in hospitals and clinics. It is implicated in hot-tub rash. It is also able to decompose hydrocarbons and has been used to break down tarballs and oil from oil spills.
Identification
It is a Gram-negative, aerobic, rod-shaped bacterium with unipolar motility.[4] An opportunistic human pathogen, P. aeruginosa is also an opportunistic pathogen of plants.[5] P. aeruginosa is the type species of the genus Pseudomonas (Migula).[6]
P. aeruginosa secretes a variety of pigments, including pyocyanin (blue-green), pyoverdine (yellow-green and fluorescent), and pyorubin (red-brown). King, Ward, and Raney developed Pseudomonas Agar P (King A medium) for enhancing pyocyanin and pyorubin production, and Pseudomonas Agar F (King B medium) for enhancing fluorescein production.[7]

Pseudomonas aeruginosa fluorescence under UV illumination
P. aeruginosa is often preliminarily identified by its pearlescent appearance and grape-like or tortilla-like odor in vitro. Definitive clinical identification of P. aeruginosa often includes identifying the production of both pyocyanin and fluorescein, as well as its ability to grow at 42°C. P. aeruginosa is capable of growth in diesel and jet fuel, where it is known as a hydrocarbon-using microorganism (or "HUM bug"), causing microbial corrosion.[3] It creates dark, gellish mats sometimes improperly called "algae" because of their appearance.[citation needed]
Although classified as an aerobic organism, P. aeruginosa is considered by many as a facultative anaerobe, as it is well adapted to proliferate in conditions of partial or total oxygen depletion. This organism can achieve anaerobic growth with nitrate as a terminal electron acceptor, and, in its absence, it is also able to ferment arginine by substrate-level phosphorylation.[8][9] Adaptation to microaerobic or anaerobic environments is essential for certain lifestyles of P. aeruginosa, for example, during lung infection in cystic fibrosis patients, where thick layers of lung mucus and alginate surrounding mucoid bacterial cells can limit the diffusion of oxygen.[10][11][12][13]

Nomenclature

  • The word Pseudomonas means "false unit", from the Greek pseudo (Greek: ψευδο, false) and monas (Latin: monas, from Greek: μονος, a single unit). The stem word mon was used early in the history of microbiology to refer to germs, e.g., Kingdom Monera.
  • The species name aeruginosa is a Latin word meaning verdigris ("copper rust"), as seen with the oxidized copper patina on the Statue of Liberty. This also describes the blue-green bacterial pigment seen in laboratory cultures of the species. This blue-green pigment is a combination of two metabolites of P. aeruginosa, pyocyanin (blue) and pyoverdine (green), which impart the blue-green characteristic color of cultures. Pyocyanin biosynthesis is regulated by quorum sensing, as in the biofilms associated with colonization of the lungs in cystic fibrosis patients. Another assertion is that the word may be derived from the Greek prefix ae- meaning "old or aged", and the suffix ruginosa means wrinkled or bumpy.[14]
  • The derivations of pyocyanin and pyoverdine are of the Greek, with pyo-, meaning "pus", cyanin, meaning "blue", and verdine, meaning "green". Pyoverdine in the absence of pyocyanin is a fluorescent-yellow color.

Gram-stained Pseudomonas aeruginosa bacteria (pink-red rods)

 Genomic diversity

The G+C-rich Pseudomonas aeruginosa chromosome consists of a conserved core and a variable accessory part. The core genomes of P. aeruginosa strains are largely collinear, exhibit a low rate of sequence polymorphism, and contain few loci of high sequence diversity, the most notable ones being the pyoverdine locus, the flagellar regulon, pilA, and the O-antigen biosynthesis locus. Variable segments are scattered throughout the genome, of which about one-third are immediately adjacent to tRNA or tmRNA genes. The three known hot spots of genomic diversity are caused by the integration of genomic islands of the pKLC102/PAGI-2 family into tRNALys or tRNAGly genes. The individual islands differ in their repertoire of metabolic genes, but share a set of syntenic genes that confer their horizontal spread to other clones and species. Colonization of atypical disease habitats predisposes to deletions, genome rearrangements, and accumulation of loss-of-function mutations in the P. aeruginosa chromosome. The P. aeruginosa population is characterized by a few dominant clones widespread in disease and environmental habitats. The genome is made up of clone-typical segments in core and accessory genome and of blocks in the core genome with unrestricted gene flow in the population.[15]

 Cell-surface polysaccharides

Cell-surface polysaccharides play diverse roles in the bacterial "lifestyle". They serve as a barrier between the cell wall and the environment, mediate host-pathogen interactions, and form structural components of biofilms. These polysaccharides are synthesized from nucleotide-activated precursors, and, in most cases, all the enzymes necessary for biosynthesis, assembly, and transport of the completed polymer are encoded by genes organized in dedicated clusters within the genome of the organism. Lipopolysaccharide is one of the most important cell-surface polysaccharides, as it plays a key structural role in outer membrane integrity, as well as being an important mediator of host-pathogen interactions. The genetics for the biosynthesis of the so-called A-band (homopolymeric) and B-band (heteropolymeric) O antigens have been clearly defined, and much progress has been made toward understanding the biochemical pathways of their biosynthesis. The exopolysaccharide alginate is a linear copolymer of β-1,4-linked D-mannuronic acid and L-glucuronic acid residues, and is responsible for the mucoid phenotype of late-stage cystic fibrosis disease. The pel and psl loci are two recently-discovered gene clusters, which also encode exopolysaccharides found to be important for biofilm formation. A rhamnolipid is a biosurfactant whose production is tightly regulated at the transcriptional level, but the precise role it plays in disease is not well understood at present. Protein glycosylation, in particular of pilin and flagellin, is a recent focus of research by several groups, and it has been shown to be important for adhesion and invasion during bacterial infection.[15]

Pathogenesis


Phagocytosis of P. aeruginosa by neutrophil in patient with bloodstream infection (Gram stain)
An opportunistic, nosocomial pathogen of immunocompromised individuals, P. aeruginosa typically infects the pulmonary tract, urinary tract, burns, wounds, and also causes other blood infections.[16]

InfectionsDetails and common associationsHigh-risk groups
PneumoniaDiffuse bronchopneumoniaCystic fibrosis patients
Septic shockAssociated with a purple-black skin lesion ecthyma gangerenosumNeutropenic patients
Urinary tract infectionUrinary tract catheterization
Gastrointestinal infectionNecrotising enterocolitis (NEC)NEC, especially in premature infants and neutropenic cancer patients
Skin and soft tissue infectionsHemorrhage and necrosisBurns victims and patients with wound infections

It is the most common cause of infections of burn injuries and of the outer ear (otitis externa), and is the most frequent colonizer of medical devices (e.g., catheters). Pseudomonas can, in rare circumstances, cause community-acquired pneumonias,[17] as well as ventilator-associated pneumonias, being one of the most common agents isolated in several studies.[18] Pyocyanin is a virulence factor of the bacteria and has been known to cause death in C. elegans by oxidative stress. However, research indicates salicylic acid can inhibit pyocyanin production.[19] One in ten hospital-acquired infections are from Pseudomonas. Cystic fibrosis patients are also predisposed to P. aeruginosa infection of the lungs. P. aeruginosa may also be a common cause of "hot-tub rash" (dermatitis), caused by lack of proper, periodic attention to water quality. The most common cause of burn infections is P. aeruginosa. Pseudomonas is also a common cause of postoperative infection in radial keratotomy surgery patients. The organism is also associated with the skin lesion ecthyma gangrenosum. P. aeruginosa is frequently associated with osteomyelitis involving puncture wounds of the foot, believed to result from direct inoculation with P. aeruginosa via the foam padding found in tennis shoes, with diabetic patients at a higher risk.

Toxins

P. aeruginosa uses the virulence factor exotoxin A to ADP-ribosylate eukaryotic elongation factor 2 in the host cell, much as the diphtheria toxin does. Without elongation factor 2, eukaryotic cells cannot synthesize proteins and necrose. The release of intracellular contents induces an immunologic response in immunocompetent patients. In addition P. aeruginosa uses an exoenzyme, ExoU, which degrades the plasma membrane of eukaryotic cells, leading to lysis.

 Triggers

With low phosphate levels, P. aeruginosa has been found to activate from benign symbiont to express lethal toxins inside the intestinal tract and severely damage or kill the host, which can be mitigated by providing excess phosphate instead of antibiotics.[20]

Plants and invertebrates

In higher plants, P. aeruginosa induces symptoms of soft rot, for example in Arabidopsis thaliana (Thale cress)[21] and Lactuca sativa (lettuce).[22][23] It is also pathogenic to invertebrate animals, including the nematode Caenorhabditis elegans,[24][25] the fruit fly Drosophila[26] and the moth Galleria mellonella.[27] The associations of virulence factors are the same for plant and animal infections.[22][28]

 Quorum sensing

Regulation of gene expression can occur through cell-cell communication or quorum sensing (QS) via the production of small molecules called autoinducers. QS is known to control expression of a number of virulence factors. Another form of gene regulation that allows the bacteria to rapidly adapt to surrounding changes is through environmental signaling. Recent studies have discovered anaerobiosis can significantly impact the major regulatory circuit of QS. This important link between QS and anaerobiosis has a significant impact on production of virulence factors of this organism.[15] Garlic experimentally blocks quorum sensing in P. aeruginosa.[29]

 Biofilms and treatment resistance

Biofilms of P. aeruginosa can cause chronic opportunistic infections, which are a serious problem for medical care in industrialized societies, especially for immunocompromised patients and the elderly. They often cannot be treated effectively with traditional antibiotic therapy. Biofilms seem to protect these bacteria from adverse environmental factors. P. aeruginosa can cause nosocomial infections and is considered a model organism for the study of antibiotic-resistant bacteria. Researchers consider it important to learn more about the molecular mechanisms that cause the switch from planktonic growth to a biofilm phenotype and about the role of interbacterial communication in treatment-resistant bacteria such as P. aeruginosa. This should contribute to better clinical management of chronically infected patients, and should lead to the development of new drugs.[15]

 Diagnosis


Production of pyocyanin, water-soluble blue pigment of Pseudomonas aeruginosa (left tube)
Depending on the nature of infection, an appropriate specimen is collected and sent to a bacteriology laboratory for identification. As with most bacteriological specimens, a Gram stain is performed, which may show Gram-negative rods and/or white blood cells. P. aeruginosa produces colonies with a characteristic 'grape-like' odour on bacteriological media. In mixed cultures, it can be isolated as clear colonies on MacConkey agar (as it does not ferment lactose) which will test positive for oxidase. Confirmatory tests include production of the blue-green pigment pyocyanin on cetrimide agar and growth at 42°C. A TSI slant is often used to distinguish nonfermenting Pseudomonas species from enteric pathogens in faecal specimens.

Treatment

P. aeruginosa is frequently isolated from nonsterile sites (mouth swabs, sputum, etc.), and, under these circumstances, it often represents colonization and not infection. The isolation of P. aeruginosa from nonsterile specimens should, therefore, be interpreted cautiously, and the advice of a microbiologist or infectious diseases physician/pharmacist should be sought prior to starting treatment. Often no treatment is needed.
When P. aeruginosa is isolated from a sterile site (blood, bone, deep collections), it should be taken seriously, and almost always requires treatment.[citation needed]
P. aeruginosa is naturally resistant to a large range of antibiotics and may demonstrate additional resistance after unsuccessful treatment, in particular, through modification of a porin. It should usually be possible to guide treatment according to laboratory sensitivities, rather than choosing an antibiotic empirically. If antibiotics are started empirically, then every effort should be made to obtain cultures, and the choice of antibiotic used should be reviewed when the culture results are available.
Phage therapy against P. aeruginosa remains one of the most effective treatments, which can be combined with antibiotics, has no contraindications and minimal adverse effects. Phages are produced as sterile liquid, suitable for intake, applications etc.[30] Phage therapy against ear infections caused by P. aeruginosa was reported in the journal Clinical Otolaryngology in August 2009[31]
Antibiotics that have activity against P. aeruginosa may include:
These antibiotics must all be given by injection, with the exceptions of fluoroquinolones, aerosolized tobramycin and aerosolized aztreonam. For this reason, in some hospitals, fluoroquinolone use is severely restricted to avoid the development of resistant strains of P. aeruginosa. In the rare occasions where infection is superficial and limited (for example, ear infections or nail infections), topical gentamicin or colistin may be used.

 Antibiotic resistance

One of the most worrisome characteristics of P. aeruginosa is its low antibiotic susceptibility, which is attributable to a concerted action of multidrug efflux pumps with chromosomally encoded antibiotic resistance genes (e.g., mexAB, mexXY etc.[33]) and the low permeability of the bacterial cellular envelopes. In addition to this intrinsic resistance, P. aeruginosa easily develops acquired resistance either by mutation in chromosomally encoded genes or by the horizontal gene transfer of antibiotic resistance determinants. Development of multidrug resistance by P. aeruginosa isolates requires several different genetic events, including acquisition of different mutations and/or horizontal transfer of antibiotic resistance genes. Hypermutation favours the selection of mutation-driven antibiotic resistance in P. aeruginosa strains producing chronic infections, whereas the clustering of several different antibiotic resistance genes in integrons favors the concerted acquisition of antibiotic resistance determinants. Some recent studies have shown phenotypic resistance associated to biofilm formation or to the emergence of small-colony variants may be important in the response of P. aeruginosa populations to antibiotics treatment.[15]

 Phosphate trigger

Phosphate has been implicated in pathogenesis of P. aeruginosa, which is normally benign. Phosphate is required by the bacteria for normal functioning, and has been shown in experiments on two very different organisms to turn on its host.[20]

 Prevention

Probiotic prophylaxis may prevent colonization and delay onset of pseudomonas infection in an ICU setting.[34] Immunoprophylaxis against pseudomonas is being investigated

Blood Sugar

Label:

    The blood sugar concentration or blood glucose level is the amount of glucose (sugar) present in the blood of a human or animal. Normally in mammals, the body maintains the blood glucose level at a reference range between about 3.6 and 5.8 mM (mmol/L, i.e., millimoles/liter), or 64.8 and 104.4 mg/dL.The human body naturally tightly regulates blood glucose levels as a part of metabolic homeostasis.
Glucose is the primary source of energy for the body's cells, and blood lipids (in the form of fats and oils) are primarily a compact energy store. Glucose is transported from the intestines or liver to body cells via the bloodstream, and is made available for cell absorption via the hormone insulin, produced by the body primarily in the pancreas.
The mean normal blood glucose level in humans is about 4 mM (4 mmol/L or 72 mg/dL, i.e. milligrams/deciliter); however, this level fluctuates throughout the day. Glucose levels are usually lowest in the morning, before the first meal of the day (termed "the fasting level"), and rise after meals for an hour or two by a few milliMolar.
Blood sugar levels outside the normal range may be an indicator of a medical condition. A persistently high level is referred to as hyperglycemia; low levels are referred to as hypoglycemia. Diabetes mellitus is characterized by persistent hyperglycemia from any of several causes, and is the most prominent disease related to failure of blood sugar regulation. A temporarily elevated blood sugar level may also result from severe stress, such as trauma, stroke, myocardial infarction, surgery, or illness[citation needed]. Intake of alcohol causes an initial surge in blood sugar, and later tends to cause levels to fall. Also, certain drugs can increase or decrease glucose levels.
Units
The international standard way of measuring blood glucose levels are in terms of a molar concentration, measured in mmol/L (millimoles per litre; or millimolar, abbreviated mM). In the United States, mass concentration is measured in mg/dL (milligrams per decilitre).[4]
Since the molecular weight of glucose C6H12O6 is about 180 g/mol, for the measurement of glucose, the difference between the two scales is a factor of 18, so that 1 mmol/L of glucose is equivalent to 18 mg/dL.[2]

Normal values

Normal value ranges may vary slightly among different laboratories. Many factors affect a person's blood sugar level. A body's homeostatic mechanism, when operating normally, restores the blood sugar level to a narrow range of about 4.4 to 6.1 mmol/L (82 to 110 mg/dL). (These levels are in contradiction with the levels cited at the beginning of this article, though the latter are quoted for mammals in general).
Despite widely variable intervals between meals or the occasional consumption of meals with a substantial carbohydrate load, human blood glucose levels tend to remain within the normal range. However, shortly after eating, the blood glucose level may rise, in non-diabetics, temporarily up to 7.8 mmol/L (140 mg/dL) or a bit more. The American Diabetes Association recommends a post-meal glucose level of less than 10 mmol/L (180 mg/dl) and a fasting plasma glucose of 5 to 7.2 mmol/L (90–130 mg/dL).[5] People with levels between 5.6 and 8 mmol/L(100-125 mg/dL) have impaired fasting glucose.
The actual amount of glucose in the blood and body fluids is very small. In a healthy adult male of 75 kg with a blood volume of 5 litres, a blood glucose level of 5.5 mmol/L (100 mg/dL) amounts to 5 grams, slightly less than two typical American restaurant sugar packets for coffee or tea.[6] Part of the reason why this amount is so small is that, to maintain an influx of glucose into cells, enzymes modify glucose by adding phosphate or other groups to it.

Regulation

The body's homeostatic mechanism keeps blood glucose levels within a narrow range. It is composed of several interacting systems, of which hormone regulation is the most important.
There are two types of mutually antagonistic metabolic hormones affecting blood glucose levels:

Health effects

If blood sugar levels drop too low, a potentially fatal condition called hypoglycemia develops. Symptoms may include lethargy, impaired mental functioning; irritability; shaking, twitching, weakness in arm and leg muscles; pale complexion; sweating; paranoid or aggressive mentality and loss of consciousness. Brain damage is even possible.
If levels remain too high, appetite is suppressed over the short term. Long-term hyperglycemia causes many of the long-term health problems associated with diabetes, including eye, kidney, heart disease and nerve damage.

Low blood sugar

Mechanisms that restore satisfactory blood glucose levels after hypoglycemia must be quick and effective to prevent extremely serious consequences of insufficient glucose: confusion or unsteadiness and, in the extreme, coma. It is far more dangerous to have too little glucose in the blood than too much, at least temporarily. In healthy individuals, blood glucose-regulating mechanisms are generally quite effective, and symptomatic hypoglycemia is generally found only in diabetics using insulin or other pharmacological treatment. Hypoglycemic episodes can vary greatly between persons and from time to time, both in severity and swiftness of onset. For severe cases, prompt medical assistance is essential, as damage to brain and other tissues and even death will result from sufficiently low blood-glucose levels.
Some healthy individuals report drowsiness or impaired cognitive function several hours after meals, symptoms which they believe are related to a drop in blood sugar, or low blood sugar. For more information, see:

Glucose measurement

Sample type

Glucose is measured in whole blood, plasma or serum. Historically, blood glucose values were given in terms of whole blood, but most laboratories now measure and report the serum glucose levels. Because red blood cells (erythrocytes) have a higher concentration of protein (e.g., hemoglobin) than serum, serum has a higher water content and consequently more dissolved glucose than does whole blood. To convert from whole-blood glucose, multiplication by 1.15 has been shown to generally give the serum/plasma level.
Collection of blood in clot tubes for serum chemistry analysis permits the metabolism of glucose in the sample by blood cells until separated by centrifugation. Red blood cells, for instance, do not require insulin to intake glucose from the blood. Higher than normal amounts of white or red blood cell counts can lead to excessive glycolysis in the sample, with substantial reduction of glucose level if the sample is not processed quickly. Ambient temperature at which the blood sample is kept prior to centrifuging and separation of plasma/serum also affects glucose levels. At refrigerator temperatures, glucose remains relatively stable for several hours in a blood sample. Loss of glucose can be prevented by using Fluoride tubes (i.e., gray-top) since fluoride inhibits glycolysis. However, these should only be used when blood will be transported from one hospital laboratory to another for glucose measurement. Red-top serum separator tubes also preserve glucose in samples after being centrifuged isolating the serum from cells.
To prevent contamination of the sample with intravenous fluids, particular care should be given to drawing blood samples from the arm opposite the one in which an intravenous line is inserted. Alternatively, blood can be drawn from the same arm with an IV line after the IV has been turned off for at least 5 minutes, and the arm has been elevated to drain infused fluids away from the vein. Inattention can lead to large errors, since as little as 10% contamination with a 5% glucose solution (D5W) will elevate glucose in a sample by 500 mg/dl or more. Remember that the actual concentration of glucose in blood is very low, even in the hyperglycemic.
Arterial, capillary and venous blood have comparable glucose levels in a fasting individual. Following meals, venous levels are somewhat lower than those in capillary or arterial blood; a common estimate is about 10%.

Measurement techniques

Two major methods have been used to measure glucose. The first, still in use in some places, is a chemical method exploiting the nonspecific reducing property of glucose in a reaction with an indicator substance that changes color when reduced. Since other blood compounds also have reducing properties (e.g., urea, which can be abnormally high in uremic patients), this technique can produce erroneous readings in some situations (5 to 15 mg/dl has been reported). The more recent technique, using enzymes specific to glucose, is less susceptible to this kind of error. The two most common employed enzymes are glucose oxidase and hexokinase.
In either case, the chemical system is commonly contained on a test strip which is inserted into a meter, and then has a blood sample applied. Test-strip shapes and their exact chemical composition vary between meter systems and cannot be interchanged. Formerly, some test strips were read (after timing and wiping away the blood sample) by visual comparison against a color chart printed on the vial label. Strips of this type are still used for urine glucose readings, but for blood glucose levels they are obsolete. Their error rates were, in any case, much higher.
Urine glucose readings, however taken, are much less useful. In properly functioning kidneys, glucose does not appear in urine until the renal threshold for glucose has been exceeded. This is substantially above any normal glucose level, and is evidence of an existing severe hyperglycemic condition. However, as urine is stored in the bladder, any glucose in it might have been produced at any time since the last time the bladder was emptied. Since metabolic conditions change rapidly, as a result of any of several factors, this is delayed news and gives no warning of a developing condition. Blood glucose monitoring is far preferable, both clinically and for home monitoring by patients. Healthy urine glucose levels were first standardized and published in 1965 [7] by Hans Renschler.

I. CHEMICAL METHODS
A. Oxidation-reduction reaction
\mathrm{Glucose} + \mathrm{Alkaline\ copper\ tartarate}\xrightarrow{\mathrm{Reduction}} \mathrm{Cuprous\ oxide}
1. Alkaline copper reduction
Folin-Wu method\mathrm{Cu}^{++} + \mathrm{Phosphomolybdic\ acid}\xrightarrow{\mathrm{Oxidation}} \mathrm{Phosphomolybdenum\ oxide}Blue end-product
Benedict's method
  • Modification of Folin-Wu method for qualitative urine glucose
Nelson-Somogyi method\mathrm{Cu}^{++} + \mathrm{Arsenomolybdic\ acid}\xrightarrow{\mathrm{Oxidation}} \mathrm{Arsenomolybdenum\ oxide}Blue end-product
Neocuproine method\mathrm{Cu}^{++} + \mathrm{Neocuproine}\xrightarrow{\mathrm{Oxidation}} \mathrm{Cu}^{++} \mathrm{neocuproine\ complex} *Yellow-orange color neocuproine[8]
Shaeffer-Hartmann-Somogyi
  • Uses the principle of iodine reaction with cuprous byproduct.
  • Excess I2 is then titrated with thiosulfate.
2. Alkaline Ferricyanide Reduction
Hagedorn-Jensen\mathrm{Glucose} + \mathrm{Alkaline\ ferricyanide}\longrightarrow \mathrm{Ferrocyanide}Colorless end product; other reducing substances interfere with reaction
B. Condensation
Ortho-toluidine method
Anthrone (phenols) method
  • Forms hydroxymethyl furfural in hot acetic acid
II. ENZYMATIC METHODS
A. Glucose oxidase
\mathrm{Glucose} + \mathrm{O}_{2}\xrightarrow[\mathrm{Oxidation}] {\mathrm{glucose\ oxidase}}\mathrm{Cuprous\ oxide}
Saifer–Gerstenfeld method\mathrm{H_{2}O_2} + \textrm{\textit{O}-dianisidine}\xrightarrow[\mathrm{Oxidation}] {\mathrm{peroxidase}} \mathrm{H_2O} + \mathrm{oxidized\ chromogen}Inhibited by reducing substances like BUA, bilirubin, glutathione, ascorbic acid
Trinder method
Kodak Ektachem
Glucometer
  • Home monitoring blood glucose assay method
  • Uses a strip impregnated with a glucose oxidase reagent
B. Hexokinase

\begin{alignat}{2}
 & \mathrm{Glucose} + \mathrm{ATP}\xrightarrow[\mathrm{Phosphorylation}] {\mathrm{Hexokinase} + \mathrm{Mg}^{++}} \textrm{G-6PO}_4 + \mathrm{ADP} \\
 & \textrm{G-6PO}_4 + \mathrm{NADP}\xrightarrow[\mathrm{Oxidation}] {\textrm{G-6PD}} \textrm{G-Phosphogluconate} + \mathrm{NADPH} + \mathrm{H}^{+} \\
\end{alignat}
  • NADP as cofactor
  • NADPH (reduced product) is measured in 340 nm
  • More specific than glucose oxidase method due to G-6PO4, which inhibits interfering substances except when sample is hemolyzed

Blood glucose laboratory tests

  1. fasting blood sugar (i.e., glucose) test (FBS)
  2. urine glucose test
  3. two-hr postprandial blood sugar test (2-h PPBS)
  4. oral glucose tolerance test (OGTT)
  5. intravenous glucose tolerance test (IVGTT)
  6. glycosylated hemoglobin (HbA1C)
  7. self-monitoring of glucose level via patient testing
  8. Random blood sugar (RBS)

Clinical correlation

The fasting blood glucose level, which is measured after a fast of 8 hours, is the most commonly used indication of overall glucose homeostasis, largely because disturbing events such as food intake are avoided. Conditions affecting glucose levels are shown in the table below. Abnormalities in these test results are due to problems in the multiple control mechanism of glucose regulation.
The metabolic response to a carbohydrate challenge is conveniently assessed by a postprandial glucose level drawn 2 hours after a meal or a glucose load. In addition, the glucose tolerance test, consisting of several timed measurements after a standardized amount of oral glucose intake, is used to aid in the diagnosis of diabetes. It is regarded as the gold standard of clinical tests of the insulin / glucose control system, but is difficult to administer, requiring much time and repeated blood tests. In comparison, the fasting blood glucose level is a much poorer screening test because of the high variability of the experimental conditions such as the carbohydrate content of the last meal and the energy expenditure between the last meal and the measurement. Actually, many people with prediabetes or diabetes can have a fasting blood glucose below the prediabetic/diabetic threshold if their last meal happened to be low in carbohydrate and they burnt all the related glucose in their blood stream before taking the test. Note that food commonly includes carbohydrates which don't participate in the metabolic control system; simple sugars such as fructose, many of the disaccarhides (which either contain simple sugars other than glucose or cannot be digested by humans) and the more complex sugars which also cannot be digested by humans. And there are carbohydrates which are not digested even with the assistance of gut bacteria; several of the fibres (soluble or insoluble) are chemically carbohydrates. Food also commonly contains components which affect glucose (and other sugar's) digestion; fat, for example slows down digestive processing, even for such easily handled food constituents as starch. Avoiding the effects of food on blood glucose measurement is important for reliable results since those effects are so variable.
Error rates for blood glucose measurements systems vary, depending on laboratories, and on the methods used. Colorimetry techniques can be biased by color changes in test strips (from airborne or finger borne contamination, perhaps) or interference (e.g., tinting contaminants) with light source or the light sensor. Electrical techniques are less susceptible to these errors, though not to others. In home use, the most important issue is not accuracy, but trend. Thus if a meter / test strip system is consistently wrong by 10%, there will be little consequence, as long as changes (e.g., due to exercise or medication adjustments) are properly tracked. In the US, home use blood test meters must be approved by the Federal Food and Drug Administration before they can be sold.
Finally, there are several influences on blood glucose level aside from food intake. Infection, for instance, tends to change blood glucose levels, as does stress either physical or psychological. Exercise, especially if prolonged or long after the most recent meal, will have an effect as well. In the normal person, maintenance of blood glucose at near constant levels will nevertheless be quite effective.[clarification needed]

Causes of abnormal glucose levels
Persistent hyperglycemiaTransient hyperglycemiaPersistent hypoglycemiaTransient hypoglycemia
Reference range, FBG: 70–110 mg/dl
Diabetes mellitusPheochromocytomaInsulinomaAcute alcohol ingestion
Adrenal cortical hyperactivity Cushing's syndromeSevere liver diseaseAdrenal cortical insufficiency Addison's diseaseDrugs: salicylates, antituberculosis agents
HyperthyroidismAcute stress reactionHypopituitarismSevere liver disease
AcromegalyShockGalactosemiaSeveral glycogen storage diseases
ObesityConvulsionsEctopic insulin production from tumorsHereditary fructose intolerance

Etymology and use of term

In a physiological context, the term is a misnomer because it refers to glucose, yet other sugars besides glucose are always present. Food contains several different types (e.g., fructose (largely from fruits/table sugar/industrial sweeteners), galactose (milk and dairy products), as well as several food additives such as sorbitol, xylose, maltose, etc.). But because these other sugars are largely inert with regard to the metabolic control system (i.e., that controlled by insulin secretion), since glucose is the dominant controlling signal for metabolic regulation, the term has gained currency, and is used by medical staff and lay folk alike. The table above reflects some of the more technical and closely defined terms used in the medical field.

Reference:
http://en.wikipedia.org/wiki/Blood_sugar