Thalassemia screening in Thailand

Abstract

The objective of thalassemia screening in Thailand is to identify a - thalassemia 1, b - thalassemia and Hb E carriers. Those with these thalassemia genes will be given appropriate genetic counseling in a prevention and control program. The aim is to prevent birth of new case with three severe thalassemia diseases including homozygous a - thalassemia 1, homozygous b - thalassemia and b - thalassemia / Hb E disease. In general, two screening strategies are performed. In the first approach, a and b - thalassemias are screened for using a one tube osmotic fragility test (OF-test) and Hb E was identified by DCIP precipitation test (DCIP test). Alternatively, screening can be done using a combined RBC indices (mean cell hemoglobin; MCH and/or mean cell volume; MCV) and a DCIP test. While positive sample at this preliminary screening will be investigated further by Hb and DNA analyses, no further test is required for those with negative result. Both screening strategies can be done effectively but application depends on laboratory facilities and technical skill of the personnel. However, quality of thalassemia screening in routine practice needs to be evaluated regularly in order to minimize false negative result.