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 Diagnostic

Laboratories (CMDL), Khon Kaen University. The KKU-Hb controls were sent to laboratory members together

with 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 result

using hematological data received and result of Hb analyses in their laboratories. The result of laboratory investigations

and the interpretations as well as the risks of having fetuses with 3 severe thalassemia diseases including homozygous

α

- thalassemia 1, homozygous β-thalassemia and β-thalassemia / Hb E disease were applied into the form provided

and 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 % of

participant laboratories could report acceptable levels of Hb A

2 and Hb F and give accurate interpretation. Members

were 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 to

be (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 A

2 and Hb F were reported quite accurately

from each laboratory member. However, when samples with complicated data were supplied, the increased in

mis-interpretation and evaluation of relative risks were observed. This result indicates the requirement of further

improvement in the laboratory interpretation and knowledge related to laboratory diagnosis of thalassemia

and hemoglobinopathies of the participants. The evaluation system developed should prove useful in both development

of external quality control program in laboratory diagnosis and further facilitate the prevention and control program

of thalassemia and hemoglobinopathies in Thailand.