Thalassemia and
abnormal hemoglobins are common
genetic disorders in Southeast Asia.
Thalassemia is not only an important public health problem but also a socio-economic problem of many countries in the region. The approach to deal with the thalassemic problem is to prevent and control births of the new cases. This requires an accurate identification of couple at high risk to have a thalassemic child. The diagnosis of
thalassemia carriers need several tests that are not practical for screening the population at large. In this study we used two simple laboratory tests to screen for potential
thalassemia carriers and
hemoglobin E individuals. Three-hundred pregnant women and 40 spouses were recruited in this study. The methods were the red cell osmotic fragility (OF) screening test with 0.36% NaCl and the
dichlorophenolindophenol (DCIP) precipitation test to detect Hb E and unstable
hemoglobins. Standard methods for red cell indices,
hemoglobin analysis and detection of
alpha-thalassemia by immunological method were also performed to confirm genotypes of
thalassemia. The results showed that 98 women (32.7%) were carriers of
thalassemias and
hemoglobin E. The number of false positive by OF test was 3.2% and by DCIP test was 0.6%. Sensitivity and specificity of OF test were 89.5% and 93.3%, respectively whereas those of DCIP test were 100%. Of the 40 couples investigated, one was found to be at risk of having
beta-thalassemia/Hb E fetus. Screening techniques including one tube osmotic fragility and DCIP precipitation tests are sensitive and specific for the detection of
thalassemia and unstable
hemoglobins such as Hb E. The techniques are also simple, economic, rapid, and give minimal false negative result.