The value of Mentzer index in the diagnosis of children thalassemia minor

Abstract

ABSTRACT Objective: To explore the effect of the Mentzer Index (MI) in screening for children thalassemia (TT) minor. Methods: We determined the MI cutoff value of diagnosing TT minor in children by utilizing a receiver operating characteristic (ROC) curve. Samples with MI values below this threshold, and no detectable gene mutations or IDA were further analyzed using Sanger sequencing or specific primer GAP-PCR. Results: In the differential diagnosis of silent α-thalassemia (α-TT) and IDA, the area under the ROC curve (AUC) for the Mentzer index (MI) was 0.561. The most Youden index indicates an MI cutoff value of 16.833, with a sensitivity of 1.000 and a specificity of 0.278. For distinguishing α-TT minor from IDA, the AUC was 0.909, with an MI cutoff value of 12.24, a sensitivity of 0.875, and a specificity of 0.778. When distinguishing β-TT minor from IDA, the AUC was 0.907, with an MI cutoff value of 11.82, a sensitivity of 0.917, and a specificity of 0.768. Utilizing these MI cutoff values, three cases of rare TT genotype were identified, including a previously unreported heterozygous mutation of IVS-II-55 (T > G) in the alpha2 (αIVS-II-55(T > G)/αα). Conclusion: The diagnostic precision of MI is limited when differentiating between silent α-TT and IDA, but it is higher when distinguishing between α-TT minor, β-TT minor, and IDA. This study established a cutoff value for MI in our laboratory, providing reliable data for screening for TT minor and discovering rare TT genotypes among children in the local area.