trevor
Forum Junior
Topics: 7
Posts: 21
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can some1 plz explain d metabolic roles of vit b12 and folate.
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| mildus
Forum Guru
Topics: 19
Posts: 614
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vitB12 has two roles:
1. deoxyadenosyl cobalamine is a cofactor of L-methyl malonyl coenzyme A mutase which converts L-methyl malonyl coenzyme A into succinyl coenzyme A
2. methylcobalamin is a cofactor of methionine synthase (or homocysteine methyl transferase) which regenerates methionine and THF (tetra hydro folate)
folate is important for group transfer (groups containing one C atome), which is important for amino acid metabolism (serine, Glycine, hystidine, methionine), timine synthesis...
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| reet
Forum Fanatic
Topics: 152
Posts: 1,411
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thanks
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| KEROCHI
Forum Guru
Topics: 60
Posts: 971
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test to detect Vit B12 def?
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| reet
Forum Fanatic
Topics: 152
Posts: 1,411
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Tests
The first indication of a vitamin B12 or folate deficiency is frequently the anemia and large red blood cells that are detected during a routine CBC (Complete Blood Count) test. Laboratory testing is used to detect a deficiency, determine its severity, establish the underlying cause of the deficiency, and to monitor the effectiveness of treatment.
Laboratory Tests
Frequently ordered to diagnose and monitor B12 and folate deficiency: B12. If low, a deficiency is indicated, but it does not identify the cause. If normal, a folate deficiency may still be present. May be ordered to monitor the effectiveness of treatment. CBC (Complete Blood Count). A group of tests ordered routinely to screen for blood cell abnormalities. It measures cell types, quantities, and characteristics. With both B12 and folate deficiency anemia, the amount of hemoglobin may be low and the RBCs (red blood cells) are abnormally large (macrocytic or megaloblastic). White blood cells and platelets also may be decreased. Folate. Either serum or RBC folate may be tested. Some believe that the RBC folate is more clinically relevant. If either is low, it indicates a deficiency. If normal, a B12 deficiency may still be present. May be ordered to monitor the effectiveness of treatment. Sometimes ordered to help determine the cause of a B12 deficiency:
SCHILLING TEST . Once frequently ordered to confirm a diagnosis of pernicious anemia. This test is no longer generally available. Intrinsic Factor Binding Antibody. Interferes with B12 binding. It may be present in those with pernicious anemia. This is a specialized test that is not commonly available. Intrinsic Factor Blocking Antibody. A protein that prevents B12 from binding to intrinsic factor. It is present in more than 50 percent of all patients with pernicious anemia. Parietal Cell Antibody. An antibody against the parietal cells that produce intrinsic factor. Present in a large percentage of pernicious anemia patients but may also be seen in other disorders. Methylmalonic Acid (MMA). Sometimes ordered to help detect mild or early B12 deficiency. Homocysteine. Occasionally ordered. May be elevated in both B12 and folate deficiency.
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| KEROCHI
Forum Guru
Topics: 60
Posts: 971
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woo... thanks..
for mle purposes schilling is still the answer.
?/
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| trevor
Forum Junior
Topics: 7
Posts: 21
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thanx reet 4 yr efforts
good luck
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| mitali
Forum Junior
Topics: 7
Posts: 33
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isn't schilling obsolete? in practice, I've found people do CBC, Vit B12 levels, IF antibodies but FA has clearly put only schilling test in its notes. is it safe to assume that the answer for B12 def testing is schilling so far as the MLE is concerned..
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| mitali
Forum Junior
Topics: 7
Posts: 33
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extension to the 2 roles of B12 you've mentioned, mildus .. 1) cofactor in the conversion of methylmalonyl CoA to succinyl CoA : hence urinary methylmalonic levels are used for Vit B12 deficiency 2) cofactor to convert homocysteine to methionine (as is folic acid) hence high homocysteine levels are also indicative of VitB12 or folic deficiency
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