关键词: 早产儿, β地中海贫血, 毛细管血红蛋白分析, 滤纸干血斑, 切值

Abstract: Objective To investigate the type and content of hemoglobin in dried blood spots in premature infants with different gestational ages, so as to determine the cut-off value of HbA in screening β-thalassemia in premature infants, thereby providing evidence for screening β-thalassemia in premature infants. Methods The components and relative content (%) of hemoglobin in dried blood spots in 5 719 premature infants from Liuzhou Center of Neonatal Screening were detected from January 2015 to December 2016 using capillary hemoglobin analysis. The cut-off value of HbA in screening β-thalassemia in premature infants was determined by data analysis and gene detection in partial premature infants with β-thalassemia. Results Main components of hemoglobin in dried blood spots in premature infants included HbA, HbF and HbA2. There were 303 (5.3%) infants with early preterm birth, 653 (11.42%) infants with moderate preterm birth and 4 763 (82.23%) infants with late preterm birth, showing the cut-off value (P₅ value of HbA) of 4.7%, 5.57% and 6.7% respectively, with significant differences among each groups (P<0.001). The cut-off value in each group was used to screen β-thalassemia in premature infants, which was highly consistent with the Results of genetic diagnosis (Kappa value =0.678,P<0.001). The sensitivity and specificity of the cut-off value of HbA in screening β-thalassemia in premature infants was 81.25% (26/32) and 86.67% (26/30), respectively. The rates of missed diagnosis and misdiagnosis were 18.75% (6/32) and 13.33% (4/30), respectively. Positive predictive value was 86.67% (26/30), negative predictive value was 81.25% (26/32), and diagnostic accordance rate was 83.87% (52/62). Conclusion Capillary hemoglobin analysis detecting HbA in dried blood spots can be used to screen β-thalassemia in premature infants.

Key words: premature infants, beta-thalassemia, capillary hemoglobin analysis, dry blood spots, cut-off values