Exploring Advances in Point-of-Care Diagnosis: Microchip Electrophoresis for Hemoglobinopathy Detection in Indian Populations

Introduction: Sickle cell anemia and thalassemia are the most prevalent inherited hemoglobinopathies globally. A point mutation in the beta-globin gene causes sickle cell disease, characterized by defective hemoglobin, severe anemia, and vaso-occlusion. A different mutation in the same gene reduces hemoglobin production, leading to beta-thalassemia with anemia, iron overload, and organ damage. C (HbC) and Hemoglobin E (HbE) are fewer common variants caused by mutations in the beta-globin gene. Approximately 7% of the world population is estimated to be carriers of such disorders and 3,00,000 – 4,00,000 babies are born every year with such diseases. About 15% of all SCD newborns worldwide are from India. Also, 10,000-15,000 babies are born with Thalassemia Major every year in the country. Early screening and identification of carriers and at prenatal stages can prevent the birth of affected offspring. The World Health Organization (WHO) estimates that early diagnosis and intervention could prevent 70% of Sickle Cell Disease (SCD) deaths with penicillin, hydroxyurea. However, in low middle income countries (LMIC) like sub-Saharan Africa and India, lack of awareness and accessibility of the diagnostic tools are the hurdles to universal screening and prevention strategies for SCD. High-Performance Liquid Chromatography (HPLC) is a widely used technology for the detection of abnormal hemoglobin variants and employed by income-rich countries as a confirmatory test. However, the small-scale laboratories in LMIC cannot often bear the cost and expertise to reliably scale up this testing especially in rural and tribal settings such as in India. Gazelle^TM is a cartridge-based microchip capillary electrophoresis technology with a portable, affordable reader system with cloud interface. This system allows real-time tracking and quantitative analysis of hemoglobin variants with a finger /heel prick, or venous blood sample, and is completed in less than ten minutes, providing results during the patient's visit.

Methods: The current study was conducted for the detection of abnormal hemoglobin variants using HPLC and microchip electrophoresis technology in two states estimated to have the highest prevalence of SCD in India.

Results: A total of 77 blood samples were processed for population surveillance in these previously unscreened regions and corroborated with HPLC. Out of 37 samples from Odisha, 32 were diagnosed with hemoglobinopathies where 14 cases had sickle cell disease, 7 cases with sickle cell trait, 6 cases with β-thalassemia trait, 4 were diagnosed as β-thalassemia major, and 1 case of HbE disease. Out of 44 samples from West Bengal, 32 were diagnosed with hemoglobinopathies. Among them, 1 case of β-thalassemia major, 8 cases of β-thalassemia trait, 3 cases of HbE disease, 7 cases of HbE trait, 1 case of sickle beta disease, 2 cases of sickle cell anemia (SCA) disease, 1 case of sickle cell trait and 8 cases of HbE β-thalassemia were observed. The results showed 99% concordance for both the testing methods. When compared to HPLC, microchip capillary electrophoresis showed 100% sensitivity, specificity, and accuracy for controls vs disease; 96% sensitivity, 97.78% specificity and 97.14% accuracy for disease vs trait; and 96.55% sensitivity, 97.56% specificity and 97.14% accuracy for trait vs disease (p =0.016).

Conclusion: Our study in a global health LMIC setting demonstrates that the microchip electrophoresis-based technology enables affordable and easy identification of common Hb variants with excellent accuracy in the field at the point of need with the same accuracy as HPLC. It is a adaptable platform for accurate diagnostic testing of SCDs and other hemoglobinopathies in low-resource regions where reliable electricity, lack of trained manpower and high cost are always prohibitive for phlebotomy-based community screening and SCD testing.