Efficiency assessment of immunochromatographic strip test for the diagnosis of alpha-thalassemia-1 carriers.

Abstract

Context:The prevention and control of thalassemia in Thailand focus on the appropriate diagnosis with a simple, cheap, and practical tool for any staff to use.Aims:(1) To screen alpha-thalassemia-1 carriers among pregnant women and spouses by immunochromatographic (IC) strip test and one tube osmotic fragility test (OFT) and (2) to evaluate the accuracy of both screening methods.Setting and Design:Cross-sectional study for 6 months duration from January to June 2013 at Kudjab Hospital located in Udonthani Province, Thailand.Subjects and Methods:Pregnant women and spouses attending the antenatal care clinic joined the study for blood sample collection (n = 414). The specimens were then taken for screening by osmotic fragility and IC strip test to specify alpha-thalassemia carriers. Another set of the specimens was sent for testing using hemoglobin (Hb) typing for thalassemia and abnormal Hb carriers and using multiplex polymerase chain reaction for alpha-thalassemia-1 carriers diagnosis as a gold standard.Results:There were 27 cases found as positive for alpha-thalassemia including alpha-thalassemia-1 carriers, South East Asian type, alpha-thalassemia-1 carriers, Thai deletion type, HbH and Hb constant spring, which were 18, 2, 3, and 2 cases, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of IC strip test were 92.6%, 95.1%, 56.8%, 99.4%, and 94.9%, respectively, which were higher than those of OFT.Conclusions:Accuracy of IC strip test was better than those of OFT. IC strip test may probably be very helpful in a massive thalassemia screening program.