Screening for thalassemia and hemoglobinopathy in a rural area of Thailand: a preliminary study.

The present study aimed to screen thalassemia and hemoglobinopathy in Baan Na-Ngam, Chachoengsao Province, Thailand. Blood samples were obtained from 266 volunteers; 105 males and 161 females aged 7 to 49 years. Blood samples screened for thalassemia combining the OF and modified DCIP precipitation tests. CBC, RBC indices, hemoglobin typing, HbA2 and Hb E were determined. Combined OF and DCIP tests found that in normal subjects, 128 out of 155 were negative for both, 3 were -/+ pattern, 22 were +/- pattern and 2 was positive for both. Interestingly, one sample showed an abnormal hemoglobin pattern, which could not be determined by automated LPLC. Three beta-thalassemia trait subjects were positive for only the OF test. For the Hb E trait, 57 out of 94 were -/+ pattern; 37 were positive for both tests. Moreover, 14 homozygous Hb E subjects were positive for both tests. The prevalence of beta-thalassemia trait was 1.1%, Hb E trait was 35.3% and homozygous Hb E was 5.3%. Since DNA analysis was not performed, alpha-thalassemia1 and alpha-thalassemia2 traits cannot be excluded. In conclusion, a combination of the OF and DCIP tests is suitable for preliminary screening for thalassemia and hemoglobinopathy. However, RBC parameters, hemoglobin typing and PCR analysis will provide more specific diagnosis, especially in alpha-thalassemias.