Innovative Parameters RET-Y, sTfR, and sTfR-F Index in Patients with Microcytic, Hypochromic Anemia—Their Special Value for Hemoglobinopathies

The role of RET-Y (the mean value of the forward-scattered light histogram within the reticulocyte population), soluble transferrin receptor (sTfR), and the ratio of soluble transferrin receptor to log10 ferritin (sTfR-F index) in discriminating hemoglobinopathies remains unclear. For that purpose, a cohort of 141 patients with microcytic, hypochromic anemia, along with 58 healthy individuals, were evaluated in the present study. Patients were divided into 4 groups: A (beta-thalassemia trait, n=62), B (iron-deficiency anemia [IDA], n=41), C (alpha-thalassemia trait, n=10) and D (hemoglobin O-Arab trait, n=28). Whole blood count, RET-Y, ferritin, sTfR, and sTfR-F index were performed for each individual. Diagnostic efficiency was analyzed by receiver operating characteristic (ROC) curves. Youden index was used for the estimation of the cutoff points and the associated values for sensitivity and 1-specificity. Statistically significant differences were observed for RET-Y, sTfR-F, and sTfR-F index between patients and healthy individuals, except for sTfR-F index of group C; between groups A, D, and B for RET-Y; between groups C, D, and B for sTfR; and between groups A, C, D, and B for sTfR-F index. ROC curves were constructed considering IDA as a positive case and indicated a very good diagnostic ability for sTfR-F index (area under the ROC curve [AUCROC]=0.938, cutoff point >2.19) in differentiating IDA from hemoglobinopathies in the study population. When the beta-thalassemia trait was considered as a positive case, ROC curves demonstrated a very good diagnostic efficiency for RET-Y (AUCROC=0.894, cutoff point <1411.8 AU). In populations where hemoglobinopathies are frequent, the full blood count, including the new parameter RET-Y, and sTfR-F index provide an extra, simple, and accurate tool for diagnosis and genetic consulting.