Interpretation
Vitamin B12 (cobalamin) is necessary for hematopoiesis and normal neuronal function.
Most (80%) plasma B12 is bound to haptocorrin (transcobalamin I); the remainder (20%) is bound to transcobalamin II, forming holotranscobalamin. Holotranscobalamin is the active form of vitamin B12.
Low B12 is seen with dietary deficiency (vegetarians), in pernicious anaemia (lack of intrinsic factor), atrophic gastritis, small bowel disease or resection, bacterial overgrowth and in pregnancy, especially the third trimester.
High B12 may be seen with vitamin supplementation, in myeloproliferative disorders and leukaemia, liver disease and hypereosinophilic syndrome.
Folate deficiency may be dietary or due to malabsorption, including Coeliac disease.
Further investigation of low or borderline vitamin B12 results may include Active B12 (holotranscobalamin), plasma methylmalonic acid (MMA) and Homocysteine.
Further investigation of low Folate may include MMA and Homocysteine.
Reference Intervals
Vitamin B12
80 – 675 pmol/L
<80 pmol/L consistent with vitamin B12 deficiency
80 – 130 pmol/L Vitamin B12 deficiency cannot be excluded. Treatment is recommended for any patient with symptoms of vitamin B12 deficiency.
Note: change of reference interval from 31/1/2023
Folate
>7 nmol/L
Test Method
CMIA Method performed on the Beckman Coulter DxI 800 analyser with Beckman Coulter Access reagents
