Table 1.
Diagnostic Parameters, References Ranges, and Potential Confounding Factors for Assessment of Vitamin B12 Deficiencya.
| Parameter | Reference Range | Confounding Factors |
|---|---|---|
| B12 | >148 pmol/L | Renal insufficiency (↑) |
| Hcy | <15 μmol/L | Renal insufficiency(↑) |
| Folate deficiency (↑) | ||
| Vitamin B6 deficiency (↑) | ||
| MMA | <260 nmol/L | Renal insufficiency (↑) |
| Age (↑) | ||
| Intestinal bacterial overgrowth (↑) |
Abbreviations: B12, vitamin B12; Hcy, homocysteine; MMA, methylmalonic acid.
aAdapted from Hermann W, Obeid R. Cobalamin deficiency. In: Stranger O, ed. Water Soluble Vitamins: Clinical Research and Future Application. Berlin, Germany: Springer; 2012:301-322.