INTRODUCTION: The sickle cell trait is the presence of hemoglobin S (HbS) in heterozygosity. According to RDC regulation 153/04, abnormal hemoglobin screening has become mandatory in blood donation samples since June 2004. OBJECTIVE: The aim of this study was to compare different screening methods used in blood banks for HbS detection. Material and method: From April 2007 to April 2008, three HbS detection methods were applied in 4,108 suitable blood samples from the blood bank of the University Hospital of Santa Maria (HUSM). The comparative study among the methods comprised solubility tests and gel-centrifuge (ID-HbS). Furthermore, the positivity reference was the presence of HbS on hemoglobin electrophoresis. RESULTS: Twenty-three (0.56%) out of 4,108 samples showed positivity for HbS and two (0.05%) showed positivity for HbC. Twenty-two (95.6%) out of 23 HbS positive samples determined through qualitative electrophoresis were detected by solubility test and 20 (86.9%) were detected by gel-centrifugation test. CONCLUSION: Hemoglobin electrophoresis proved the best method in the identification of hemoglobin variants and, therefore, worthwhile when it comes to diagnostic screening in blood banks due to its high sensitivity, which keeps false-negative results to a minimum and ensures blood quality.
Hemoglobin S; Sickle cell trait; Solubility test; Gel-centrifuge test; Hemoglobin electrophoresis
