Accuracy of Immunochromatographic Strip Test in Diagnosis of Alpha-Thalassemia-1 Carrier
Chanane Wanapirak MD*, Wirawit Piyamongkol MD*, Supatra Sirichotiyakul MD*, Chatchai Tayapiwatana PhD**,***, Watchara Kasinrerk PhD**,***, Theera Tongsong MD*
Affiliation : * Maternal-Fetal Medicine Unit, Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand ** Division of Clinical Immunology, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand *** Biomedical Technology Research Center, National Center for Genetic Engineering and Biotechnology, National Sciences and Technology Development Agency at the Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
Objective : To determine the accuracy of alpha-Thal Immunochromatographic (IC) strip in diagnosis of alpha-thalassemia 1
carrier among pregnant women, using PCR for alpha-thalassemia 1 (SEA type) as a gold standard.
Material and Method: Asymptomatic pregnant women attending the antenatal care clinic were recruited. Their blood
samples were taken for IC Strip Test (α Thal IC strip, i+Med Laboratories Company Limited) in predicting alpha-thalassemia
1 carrier and separately sent for PCR for diagnosis of α-thalassemia 1 carrier as a gold standard.
Results : Four hundred ninety nine pregnant women were recruited into the present study at various gestational weeks. The
accuracy of alpha-Thal IC strip test was relatively high as shown in Table 1. Of them, 62 cases were proven to be alpha-
thalassemia 1 trait and all of them had the results of positive IC strip, giving a sensitivity of 100%. However, 45 pregnant
women of non-α-thalassemia 1 trait had positive test, giving a specificity of 89%.
Conclusion : The present study was solid evidence for clinical application of α-thal IC strip in screening program of
thalassemia to reduce the need for PCR in diagnosis of α-thalassemia 1 carrier because of its very high sensitivity. The
negative test reassures the non α-thalassemia 1 carrier status. Moreover, due to its simplicity, convenience to use, low cost,
less-time consuming, clear interpretation and no need for either equipment or expensive laboratories, it may probably be very
helpful in a massive screening program.
Keywords : Immunochromatographic strip, Thalassemia carrier, Pregnancy
