A cost effective approach to the biochemical diagnosis of iron deficiency.

Serum iron, total iron binding capacity (TIBC) and serum ferritin were measured on 419 samples to evaluate the value of these measurements and to develop a cost effective strategy for diagnosis of iron deficiency. If transferrin saturation (PS) of less than 16% and TIBC of greater than 70 mumol/L were used as diagnostic criteria for iron deficiency, 93% of the 59 patients who fulfilled these criteria were iron deficient; 49 had low serum ferritin and six were iron deficient with normal serum ferritin levels. When we used PS of greater than or equal to 22% and TIBC less than or equal to 70 mumol/L to exclude iron deficiency, 99% of those patients who fulfilled these criteria had normal serum ferritin levels. We, therefore, suggest that for biochemical diagnosis of iron deficiency serum iron and TIBC should be done first, and serum ferritin is not required when the PS is less than 16% and TIBC greater than 70 mumol/l or if PS is greater than or equal to 22% and TIBC less than or equal to 70 mumol/L. In all other cases serum ferritin is measured to detect iron deficiency. This approach will save 35 to 40% of reagent costs.