Seven fulfilled at least one criterion for tissue B12 deficiency
1 µg/d of B12 p.o.
Serum B12 rose to 64 pmol/L (87 pg/mL), well below normal; gastritis may have decreased absorption of any B12 inadvertently present in the food
Half had serum B12 values < 74 pmol/L (100 pg/mL)
0.07–0.25 µg/d of B12
0.3–0.65 µg/d of B12
Hematological responses seen but serum B12 ≤ 74 pmol/L (100 pg/mL) in all
Interpretation complicated by transfusions and intramuscular injections
c SD = standard deviation.
d NA = not available.
Possible Ancillary Method: Maintenance of a Serum B12Concentration That Is Consistent with a Normal Circulating MMA Value
Several investigators have urged the use of the serum MMA concentration as the most sensitive indicator of B12 status (Lindenbaum et al., 1990; Moelby et al., 1990; Savage et al., 1994b; Stabler et al., 1996). This indicator could not be used as the criterion for setting