Optimizing Testing Time for Methaemoglobin Reduction Test in G6PD Screening: A Comparative Experimental Study between the Monica Cheesbrough Protocol and the Asutifi North District Hospital Protocol at Asutifi North District Hospital, Ghana.

Abstract

Background: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an inherited disorder caused by a genetic defect in the red blood cell enzyme G6PD, affecting around 500 million people worldwide. The study investigated the optimum methaemoglobin reduction test (MRT) reaction time for diagnosing G6PD deficiency among patients at Asutifi North District Hospital using Monica Cheesbrough protocol and Asutifi North District Hospital Protocol. Methodology: The study was an experimental study conducted with 643 participants from April, 2024 to July, 2024. The Monica Cheesbrough MRT and the Asutifi North Hospital MRT protocols, were compared at various time points (T90, T120, T150, and T180 minutes). Intraclass Correlation Coefficient (ICC) and Kappa statistics were used to assess reliability and agreement between the results from the two protocols. McNemar's test was utilized to analyse G6PD status differences between the protocols. The prevalence of G6PD deficiency was also determined. Data analysis was done using IBM Statistical Package for the Social Sciences version 26.0 (2019. Armonk, NY: IBM Corp). P-value less than 0.05 was considered statistically significant for all analysis. Results: T90 ICC values were very low (0.005-0.007), indicating poor agreement. From T120 onwards, ICC values were high (0.967-0.996, p<0.001), demonstrating excellent reliability. Significant differences in G6PD status were found at T90 (p<0.001), with diminishing differences at later time points. Kappa values indicated slight agreement at T90 (K=0.164, p<0.001) and perfect agreement from T120 onwards (K=1.000, p<0.001). The majority of participants 606 (94.2%) had normal G6PD status, 29 (4.5%) had a fully defective enzyme, and 8 (1.2%) had a partially defective enzyme activity. Conclusion: The study found the optimum MRT reaction to be 120 minutes. The study also emphasized lesser volumes of blood samples and reagent give accurate results in the optimum time established. These insights can help in both sample and reagent management especially amongst paediatric patients where it is difficult taking very large volumes of blood for testing.