Development and Validation of an ELISA for Hemoglobin‐A₂: A Novel Method for β‐Thalassemia Screening in Developing Countries

Abstract

Hemoglobin‐A₂ (HbA₂) measurement in human hemolysates has great significance, since its level can indicate β‐thalassemia carrier status in other-wise healthy individuals. An ELISA for HbA₂ using antiserum mono‐specific to the δ chain of HbA₂ and affinity purified antirabbit gamma globulins (ARGG) conjugated to horseradish peroxidase (HRP) have been developed. The monospecific antiserum used does not cross react with other hemoglobins. Hemolysates from volunteers are used for measurement of HbA₂. In a limited trial for β ‐thalassemia carrier screening (n = 350), the results obtained with the developed ELISA are comparable with those obtained with a micro‐column chromatography method (r ≥ 0.89). The developed ELISA is simple, accurate, precise, inexpensive, and several samples can be processed simultaneously with ease, making this system a suitable candidate for transforming into a user friendly kit.

Keywords:

• Hemoglobin‐A₂
• ELISA
• β‐Thalassemia
• Hemolysates

Acknowledgments

This publication (NIRRH/8/2003) has been supported by the Indian Council of Medical Research. The authors acknowledge Dr. C.P. Puri, Director of NIRRH, for the support given to this study. Thanks are also due to Dr. S. S. Tongaonkar, Animal Disease Research Laboratory, NDDB, Anand, for raising the antisera to rabbit IgG in goats.