Thalassemia in the outpatient department of the Yangon Children's Hospital in Myanmar: basic hematological values of thalassemia traits.

The present study was conducted in the Outpatient Department (OPD) of Yangon Children's Hospital (YCH) during June to November 1990 to determine the hematological data of 133 Myanmar patients with thalassemia trait who were the parents of patients with known beta-thalassemia major or hemoglobin E (Hb E)/beta-thalassemia. The mean values of hemoglobin (Hb) concentration, packed cell volume (PCV), mean cell hemoglobin (MCH) and mean cell volume (MCV) were significantly lower than normal controls but the mean cell hemoglobin concentration (MCHC) was the same as controls. Increased osmotic resistance tested in 0.36% buffered saline was detected in 81-97% of cases depending on the cut-off point. High levels of Hb A2 (> 3.5%) were found in 93% of cases whereas Hb F was increased (> 0.8%) only in 23% of cases. Although the mean red cell count (RBC) was significantly higher than normal, only 79% of thalassemia traits were detected if the RBC count of > 5.0 x 10(12)/1 was taken as the discrimination limit. Other discrimination functions such as MCH/RBC, MCV/RBC, (MCV)2 x MCH x 0.01 and MCV-(RBC/10(12)/1)-(5 x Hb) - 3.4 or - 8.4 were tested for their utility in diagnosing thalassemia traits. All of them were found not to be superior to each of the simple tests (MCV, MCH, Hb A2 or osmotic fragility) in diagnosing thalassemia traits. The one tube osmotic fragility test is a the suitable test to be used in future thalassemia screening programs in Myanmar.