Service of DNA analysis for thalassemia at Khon Kaen University: Situation of thalassemia genes analysis service unit at Khon Kaen University : Casec sase study of unwanted events

Abstract

Thalassemia in Thailand is very heterogeous. Selection of appropriate testing for thalassemia genes targeted for prevention and control is important. This requires accurate results of both screening test and Hb analysis. A retrospective data on thalassemia gene analysis for prevention and control of 3 severe thalassemia diseases including homozygous α-thalassemia 1, homozygous β-thalassemia and β-thalassemia/ Hb E at the thalassemia service unit, Centre for Research and Development of Medical Diagnostic Laboratories. Faculty of Associated Medical Sciences, Khon Kaen University during January 2013 – September 2014 was analyzed. Among 1,079 at risk couples encountered, 644 fetal specimens were also obtained for prenatal diagnosis. Among these 1,079 couples, specimens were obtained with complete primary screening and Hb analysis results and correct risk assessment for the fetuses in 789 couples (73.1%). Specimens from the remaining 290 couples (26.9 %) were obtained with 5 unwanted events including 1. No primary screening and Hb analysis results (n = 34; 3.1 %) 2. Incomplete screening and/or Hb analysis results (n = 48; 4.4 %) 3. Incorrect primary screening and/or Hb analysis results (n = 26; 2.4 %) 4. Incorrect and/or incomplete risk assessment of the fetus (n = 16; 1.5 %) and 5. No risk for 3 severe thalassemia diseases (n = 166; 15.4 %). Among 166 couples with no risk, 50 fetal specimens were also obtained for prenatal diagnosis. It was found that expected proportion (1 to 4) of affected fetuses with severe thalassemia diseases in the fetuses was encountered for a group with accurate referring but this was 1 to 10 in a group with unwanted events. This has led to unnecessary workload, delaying turnaround time, inaccurate results and unnecessary cost of laboratory investigation which could affect the couples as well as the overall efficiency of a prevention and control program. To reduce these unwanted events, related medical personnel should understand limitation of each laboratory test at screening, Hb analysis and gene analysis and they should practice in depth how to integrate all laboratory results into accurate interpretation.