Diagnosing Beta Thalassemia trait in a developing country

Beta Thalassemia trait (BTT) is diagnosed by detecting hemoglobin A2 (HbA2) >3.8% on either High Performance Liquid Chromatography (HPLC) or cellulose acetate electrophoresis (CAE). HPLC is an accurate and reproducible but costly alternative to more conventional CAE which is labor intensive but easy to interpret and inexpensive. To determine the sensitivity of CAE and HPLC keeping PCR as gold standard for the diagnosis of BTT. Cross sectional. Armed Forces Institute of Pathology Rawalpindi. May 2014 to January 2015. Five ml EDTA anti-coagulated blood was collected from 100 PCR proven cases of BTT. HbA2 levels were measured by running samples directly on HPLC. But for CAE, first a hemolysate was prepared which was then applied to cellulose acetate membrane at an alkaline pH (7.9). After elution of HbA2 band in Tris EDTA borate buffer (pH of 8.9), HbA2 concentration was calculated by measuring its absorbance in a photometer at a wavelength of 416 nm. Mean age of the patients was 28.8 ± 8.1 year. The most common mutation was Fr 8–9 (35%) followed by IVS1-5 (25%) mutation. Mean HbA2 levels by CAE and HPLC were 4.97 ± 0.42 and 5.54 ± 0.59 respectively. All the patients had HbA2 > 4% on both CAE and HPLC. None of our patients had false negative result either on CAE or HPLC. CAE has comparable sensitivity with HPLC for detection of Beta Thalassemia Trait.