Improved Detection of Early Iron Deficiency in Nonanemic Subjects
- Suzanne McClure, MD, PhD;
- Edward Custer, PhD;
- J. David Bessman, MD
Abstract
We measured the complete blood cell count, including the index of RBC size heterogeneity (RBC distribution width [RDW]), in 181 subjects without anemia to determine whether RDW became abnormal earlier in the development of iron deficiency than did other variables. In 163 subjects selected only for otherwise normal blood cell counts, an increased RDW was 66% specific (48/73) and 100% sensitive (48/48) for decreased serum iron saturation. Stool guaiac testing was equally specific but less sensitive. In 13 subjects with polycythemia, as iron deficiency developed, RDW increased a minimum of four weeks before mean cell volume changed. In one apparently normal young woman, an abrupt isolated rise in RDW revealed a newly developed low serum transferrin saturation; all values remained normal during serial testing of four other normal subjects. We conclude that RDW is the part of the routine blood cell count that first becomes abnormal during the development of iron deficiency.
(JAMA 1985;253:1021-1023)
Footnotes
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Presented in part at the annual meeting of the American Society for Clinical Investigation, Washington, DC, May 1984.
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Reprint requests to John Sealy Hospital, MW 404, University of Texas Medical Branch, Galveston, TX 77550 (Dr Bessman).
