[Value of Analyzing Hemoglobin A₂ by ROC Curve for Screening Thalassemia]

To investigate the value of hemoglobin A₂(HbA₂) for screening thalassemia.

A total of 2 000 adults' peripheral blood samples from Guangdong Women and Children Hospital from June 2013 to January 2014 were collected. The hemoglobin A₂ (HbA₂) level was analyzed by the full automatic capillary electrophoresis technique, and the genotypes of thalassemia were detected.

The optimal cutoff values of HbA₂ for screening silent α-thalassemia, α-thalassemia trait, intermedia α-thalassemia and β-thalassemia trait were 2.85%, 2.65%, 2.25% and 3.45%, respectively; the areas under receiver operator characteristic (ROC) curve were 0.709, 0.839, 0.979 and 0.997 respectively; the sensitivities were 0.481, 0.721, 0.953 and 0.994, and the specificities were 0.846, 0.837, 0.929 and 0.969 respectively.

The optimal cutoff values of HbA₂ for screening different type of thalassemia based on our laboratory data are established by using ROC curve. According to the area under ROC curve, a satisfactory accuracy for screening intermedia α-thalassemia and β-thalassemia trait can be achieved by detecting hemoglobin A₂ level.