Status of laboratory testing in the diagnosis of megaloblastic anemia.

By John Lindenbaum W HAT WAS ONCE relatively straightforward, seems lately to have become more confusing. In the past decade, new opportunities and new problems in the diagnostic approach to the patient with a possible megaboblastic anemia have appeared with the development and nearly ubiquitous use of new technobogies-electronic determination of the mean corpuscubar volume (MCV) and an apparent myriad of “easyto-do” radioisotope dilution assays (RIDs) of serum cobalamin and folate bevels. Hopefully, the following brief summary of the state of the art may serve as a temporary guide to the perplexed.