Rimon et al1 provide an original investigation about the diagnostic value of transferrin receptor–ferritin (TR-F) index for the diagnosis of iron deficiency anemia in the elderly. They find a high specificity (93%) and sensitivity (88%) compared with the low sensitivity (16%) of a routine laboratory test set. The reference range of ferritin level used in this study (men, 24-300 ng/mL; women, 15-307 ng/mL) is probably indicated by the manufacturer of ferritin assay. However, the lower limit value of serum ferritin used in elderly people should be increased. For example, Holyoake et al2 find evidence that a plasma ferritin level of 45 ng/mL or less is the best cutoff value to diagnose iron deficiency anemia in a geriatric medical unit. Another study3 reveals that an investigation of the gastrointestinal tract should be performed in elderly patients with a ferritin level less than 50 ng/mL, irrespective of the hemoglobin level. Significant lesions, including colonic cancer, are found in 51% of these cases.
Ruivard M, Gerbaud L, Doz M, Philippe P. Ferritin Is More Cost-effective Than Transferrin Receptor–Ferritin Index for the Diagnosis of Iron Deficiency. Arch Intern Med. 2002;162(15):1783. doi: