Proficiency testing in laboratory diagnosis of common thalassemia and hemoglobinopathies in Thailand

ABSTRACT

To improve the efficiency of laboratory diagnosis of common thalassemia and hemoglobinopathies in Thailand,the proficiency testing program was set up at the Centre for Research and Development of Medical DiagnosticLaboratories (CMDL), Khon Kaen University. The KKU-Hb controls were sent to laboratory members togetherwith essential hematological parameters. Each time, two control samples designated as husband and wife were sent.Upon receiving, all laboratory members analyzed control samples in their routine practices and interpreted the resultusing hematological data received and result of Hb analyses in their laboratories. The result of laboratory investigationsand the interpretations as well as the risks of having fetuses with 3 severe thalassemia diseases including homozygousα- thalassemia 1, homozygous β-thalassemia and β-thalassemia / Hb E disease were applied into the form providedand sent back to CMDL. Three cycles were investigated with 21, 23 and 66 participant laboratories, respectively.All control samples were received within appropriate times and conditions. It was found that more than 90 % ofparticipant laboratories could report acceptable levels of Hb A2 and Hb F and give accurate interpretation. Memberswere analyzed and grouped into 4 different quality groups;Excellent, Good, Fair and Need improvement.The proportions of members in the Excellent, Good, Fair and Need improvement groups were respectively found tobe (81.0, 9.5, 4.75 \& 4.75 %) in the first cycle and (69.6, 0, 21.7 \& 8.7 %) in the second cycle and (56.0, 18.2,24.3 \& 1.5 %) in the third cycle. It was found that the values of Hb A2 and Hb F were reported quite accuratelyfrom each laboratory member. However, when samples with complicated data were supplied, the increased inmis-interpretation and evaluation of relative risks were observed. This result indicates the requirement of furtherimprovement in the laboratory interpretation and knowledge related to laboratory diagnosis of thalassemiaand hemoglobinopathies of the participants. The evaluation system developed should prove useful in both developmentof external quality control program in laboratory diagnosis and further facilitate the prevention and control programof thalassemia and hemoglobinopathies in Thailand.