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Assessment of Vitamin B12 Deficiency
Following methods are used to assess the Deficiency of Vitamin B12:
1. Serum B12:
- It is quantitated by radioimmunoassay or by ELISA.
2. Schilling test:
- Radioactive labelled (Cobalt-60) Vitamin B12, one microgram is given orally.
- In gastric atrophy cases, there is no absorption, hence the entire radioactivity is excreted in feces and radioactivity is not observed in liver region.
- If the cause is nutritional deficiency, there will be enhanced absorption. Then radioactivity is noted in the liver region, with very little excretion in feces.
3. Methyl malonic acid:
- It is seen in urine.
4. FIGLU excretion test
5. Peripheral smear:
- Peripheral blood and bone marrow morphology shows megaloblastic anemia.
- If megaloblastic anemia is treated with folic acid alone, the anemia may improve, but associated neurological symptoms are aggravated.
- Hence all macrocytic anemias are generally treated with folate and Vitamin B12.
- Therapeutic dose of Vitamin B12 is 100 to 1000 microgram by intramuscular injections.
Daily requirement of Vitamin B12
- Normal daily requirement is 1–2 mg/day. During pregnancy and lactation, this is increased to 2 mg/day.
- Those who take folic acid, should also take Vitamin B12.
- Elderly people are advised to take Vitamin B12 supplementation.
Dietary sources of Vitamin B12
- Dietary Sources Vitamin B12 is not present in vegetables.
- Liver is the richest source.
- Curd is a good source, because lactobacillus can synthesize Vitamin B12.
FOR COMPLETE LESSON PEASE VISIT THE VITAMINS SECTION IN BIOCHEMISTRY 1.