Validation of the immunochromatographic strip for α-thalassemia screening: a multicenter study.

Abstract

α(0)-Thalassemia occurs from a deletion of 2 linked α-globin genes and interaction of these defective genes leads to hemoglobin (Hb) Bart's hydrops fetalis, the most severe and lethal thalassemia syndrome. Identification of α(0)-thalassemia carriers is thus essential for the prevention and control program. An immunochromatographic (IC) strip test was developed for rapid screening of α(0)-thalassemia by testing for Hb Bart's in the blood samples using a specific monoclonal antibody against Hb Bart's. To evaluate its sensitivity and specificity, the IC strip test was assessed in a cohort with various thalassemia genotypes from 4 different laboratories in Thailand and Australia. The result showed 97% sensitivity in α-thalassemia carriers with 2 α-globin genes deletion and Hb H disease. This is, in particular, the useful rapid screening test for regions where β-thalassemia and homozygous Hb E are also common. Similar hematologic and Hb data make it impossible to address the concomitant inheritance of α(0)-thalassemia in these samples without polymerase chain reaction (PCR)-based techniques, leading to misdiagnosis of the risk of having Hb Bart's hydrops fetalis. However, α-globin genotyping should be carried out in samples with positive IC strip as positive reactivity was also observed in homozygous α(+)-thalassemia carriers who have 2 trans α-globin gene deletions. These results indicate that in combination with red blood cell indices, the IC strip test could rule out mass populations for further α(0)-thalassemia detection by PCR-based analysis. The Alpha Thal IC strip also has the potential to replace testing for Hb H inclusion bodies, as it appears to be more sensitive, specific, and less labor intensive.

• Authors: Pranee Winichagoon, Pornnapa Kumpan, Paula Holmes, Jill Finlayson, Christopher Newbound, Arnold Kabral, Benjamin Li, Manit Nuinoon, Terry Fawcett, Chatchai Tayapiwatana, Watchara Kasinrerk, Suthat Fucharoen
• Journal: Translational research : the journal of laboratory and clinical medicine (Transl Res) Vol. 165 Issue 6 Pg. 689-95 (Jun 2015) ISSN: 1878-1810 [Electronic] United States
• PMID: 25450870 (Publication Type: Journal Article, Multicenter Study, Research Support, Non-U.S. Gov't, Validation Study)
• Copyright: Copyright © 2015 Elsevier Inc. All rights reserved.

Topics

• Chromatography, Affinity (instrumentation)
• Genotype
• Humans
• alpha-Thalassemia (diagnosis, genetics)