Abstract:

Objective To study the role of hemoglobin（Hb） A₂,mean corpuscular volume（MCV） and mean corpuscular hemoglobin（MCH） combined determination scheme for screening thalassemia. Methods The HbA₂ levels of α-thalassemia group,light β-thalassemia group and healthy subjects（healthy control group） were determined,and the results were analyzed comparatively. The efficiency of HbA₂ for screening thalassemia was evaluated by receiver operating characteristic（ROC） curve. The performance of the scheme was evaluated through screening 322 clinical suspected cases of thalassemia. Results The HbA₂levels in α-thalassemia group,light β-thalassemia group and healthy control group had statistical significance（P<0.05）,but there was no statistical significance among stationary type,standard type and intermediate type α-thalassemia groups and healthy control group（P>0.05）. The diagnostic cut-off values for screening α-thalassemia and light β-thalassemia were HbA₂<3.05% and HbA₂>3.90%,respectively. The sensitivity,specificity,positive predictive value,negative predictive value and consistency rate were 76.33%,58.82%,67.19%,69.23% and 68.10%,respectively. Conclusions The scheme,MCV<82.1 fL and（or） MCH<27.3 pg with HbA₂<3.05% or HbA₂>3.90%,has a good performance for screening thalassemia. It should carry on relevant auxiliary determination or detect thalassemia gene directly for suspected α-thalassemia patients.

Key words: Hemoglobin A₂, Thalassemia, Receiver operating characteristic curve