Differentiation between Thalassemia Trait and Iron Deficiency Anemia Based on Low Hemoglobin Density and Microcytic Anemia Factor.

Background: The most common causes of microcytic hypochromic anemia are thalassemia trait (TT) and iron deficiency anemia (IDA). Clinically, the differential diagnosis of TT and IDA is crucial, but it is typically challenging. Thus, in order to differentiate between TT and IDA, we seek to develop a new discriminative index on an automatic hematology analyzer utilizing the two new RBC characteristics of low hemoglobin density (LHD) and microcytic anemia factor (MAF).
Methods: We recruited a total of 323 subjects, including 115 healthy controls, 83 TT, and 125 IDA. An automated hematology analyzer (DxH800, Beckman Coulter) was used to determine peripheral blood parameters; LHD and MAF were calculated using the parameters of MCHC, Hb, and MCV. The receiver operating characteristic (ROC) curve was used to determine the cutoff values and evaluate the diagnostic value for TT and IDA.
Results: LHD was significantly lower in TT than IDA, whereas MAF was higher. To distinguish between TT and IDA, a new formula based on LHD and MAF was developed, with a cutoff value of 0.5, AUC of 0.9706 (95% CI: 0.9503 - 0.9909), and specificity, sensitivity, positive predictive value, and negative predictive values were 92.91%, 91.36%, 89.16%, and 94.40%, respectively. The new formula has proven advantages over conventional indices, such as RDW-SD, MCV, MCH, etc. Conclusions: The RBC parameters LHD and MAF detected by hematology analyzer could be useful for screening for TT and IDA. Our new formula outperforms other discriminant formulas in the literature with high sensitivity and specificity, is simple, rapid, and can aid in early detection and management.