Table 1: Traditional and evidence-based vitamin B12 deficiency reference values.

Assessment

Traditional assessment cutoffs

Evidence-based assessment cutoffs

Serum B12

< 148 pmol/L (< 200 pg/ml)

< 300 pmol/L (< 405 pg/ml)

Homocysteine

> 15 mol/L

≥ 10 mol/L

Holo TC II

< 35 pmol/L

< 50 pmol/L

Serum MMA

> 260 nmol/L or > 271 nmol/L

> 260 nmol/L or > 271 nmol/L

Urinary MMA

> 4.3 mol/L

> 4.0 mol/L

Urinary MMA/creatinine

> 4.8 mmol/L creatinine

> 3.5 mmol/L creatinine

MCV

> 98 m3/cell

> 98 m3/cell