Together with our results, the findings of Drs Aguirre and Barreiro support that there is a need for clearer recommendations regarding the use of laboratory tests for diagnosing vitamin B12 deficiency. Furthermore, the studies call attention to the fact that other biochemical markers might be of relevance. For that purpose cobalamin-saturated transcobalamin has been suggested as an early marker of vitamin B12 deficiency,1 and recently a method has been developed that in the future will allow the establishment of routine methods suitable for measurement of this component.2
Hvas A, Ellegaard J, Nexø E. Methylmalonic Acid and Clinical Practice—Reply. Arch Intern Med. 2002;162(1):103–104. doi:
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