ABSTRACT
Objective To evaluate the detection competence of HbA2 and HbF in Guangxi medical laboratories.Methods The external quality assessment(EQA) of HbA2 and HbF was conducted twice a year and five samples was detected each time during 2012 to 2016.The laboratories participated in EQA completed the samples' detection and submitted the detection results at specified time according to the requirements of EQA.The distribution of each detection system,the qualification rate of each laboratory,the variation degrees of each detection system and each detection method,and the variations of results for different levels of quality control(QC) materials during 5 years were analyzed based on the returned results.Results The application of high performance liquid chromatography (HPLC) and capillary electrophoresis(CE) increased year by year and their usage rates in 2016 reached up to 46.1％ (82/178) and 18.0％ (32/178),respectively.The qualification rates of HbA2 and HbF increased from 51.5％ (34/66) and 60.6％ (40/66) in 2012 to 93.3％ (166/178) and 92.1％ (164/178) in 2016,respectively.The average coefficient of variation(CV) of each detection system decreased year by year.There were good CVs for the results of high,medium and low levels of HbA2 QC materials detected by the Bio-Rad Variant Ⅱ and Sebia CAPILLARYS 2 systems,and they were less than 6.0％.HPLC and CE could quantitatively detect the HbA2 and HbF levels,and their total detection competence was superior to that of agarose gel electrophoresis.Conclusion EQA can assess the abihty of one laboratory detecting HbA2 and HbF,and quantitatively analyze the levels of HbA2 and HbF,which may provide the quality assurance and data support for the screening and prevention of thalassemia.
ABSTRACT
Background & objectives: β-thalassaemia is a genetic disorder and an important health problem around the world. Quantitative haemoglobin A2 (HbA2) levels are used for the diagnosis of β-thalassaemia. The conventional methods are high performance liquid chromatography (HPLC), electrophoresis, and microcolumn chromatography techniques. We established a fast protein liquid chromatography (FPLC) method, to measure quantitatively of HbA2 levels, and compared its efficacy with conventional methods. Methods: The FPLC method, using a DEAE Sepharose, Hi Trap anion-exchange column chromatography technique was set up for HbA2 measurement. In this study, 220 blood samples were screened for haemoglobin type by FPLC technique and also using HPLC, microcolumn chromatography and electrophoresis. Results: The FPLC results were highly correlated (r = 0.985, P<0.001) with those of HPLC for quantification of HbA2 as well as cellulose acetate electrophoresis (r = 0.977) and microcolumn chromatography (r = 0.980). The FPLC method showed 100 per cent sensitivity and specificity, positive and negative predictive value for β-thalassaemia diagnosis. In addition, the FPLC method was simple, rapid, low cost and reproducible. The HbA2/E range of FPLC for β-thalassaemia was 6-10 per cent, HbE trait was 10-40 per cent, β-thalassaemia/HbE was 40-60 per cent and homozygous HbE was more than 60 per cent. Interpretation & conclusions: Our findings suggested that FPLC method could be used as a cost-effective method for routine β-thalassaemia diagnosis.