A Novel Parameter for the Diagnosis of Iron Deficiency: The Transferrin/Albumin Ratio.

Iron deficiency (ID) is generally easily diagnosed by a serum ferritin concentration less than 12 μg/L. However, in patients with concomitant pathologies, sensitivity of ferritin for diagnosing ID is low, since inflammation or liver disease can lead to normal or increased ferritin values, even when iron deficiency. In this study, we propose a new marker for diagnosing ID in patients with chronic disease: the Transferrin/Albumin ratio (Tf/A ratio). Indeed, the synthesis and the elimination of albumin and transferrin are regulated by similar processes, excepted in ID. In the latter, the synthesis of transferrin is stimulated, whereas that of albumin is not. Therefore, the Tranferrin/Albumin ratio increases in case of ID, even when transferrin values are within the normal range. To determine the accuracy of this novel parameter, we studied 75 patients with chronic disease who were submitted to bone marrow aspirates and iron staining. Iron stores depletion was defined by less than 10% sideroblasts, without extra-cellular iron nor siderocytes. Blood samples were routinely undertaken at the time of the medullar sampling for determination of hematological and biochemical parameters. Iron status including ferritin, Tranferrin Saturation (TfSat), soluble Transferrin Receptor (sTfR), sTfR/log ferritin and Tf/A ratio, was determined. The diagnostic accuracy of the Tf/A ratio was compared to previously described parameters of iron status that we cited above. Receiver Operating Characteristics (ROC) curves were built to determine the best cut-off values for the prediction of iron deficiency. According to the Perls’ reaction, 25 of the 75 patients (33%) had depleted iron stores and 50 had normal or increased iron stores. Sixteen iron-depleted patients (67%) had anemia. Mann and Whitney U test showed that parameters significantly associated with ID were: Tf, Tf/A ratio, ferritin, TfSat, sTfR, sTfR/log ferritin, mean corpuscular volume, mean corpuscular hemoglobin, red blood cell and reticulocyte counts. In a multivariate analysis, the only significant, independent predictor of iron depletion was the Tf/A ratio (r = 0.637, p < 0.005). The sensitivity/specificity of Tf/A ratio at a cut-off point of 6.4% as given by ROC curve were 80%/88%. In conclusion, the Tf/A ratio is useful in the detection of iron depletion in patients with chronic disease and could dispense with bone marrow aspirate and Perls’ reaction in more than 80% of cases.