Ferritin Is More Cost-effective Than Transferrin Receptor–Ferritin Index for the Diagnosis of Iron Deficiency

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.