Evaluation of a flow cytometric test for G6PD‐deficient erythrocytes. Issue 4 (2nd February 2021)

• Record Type: Journal Article
• Authors: Kapadia, Alpeshkumar Bipinbhai; Sharma, Prashant; Jain, Karuna; Sachdeva, Man Updesh Singh; Bose, Parveen Lata; Gupta, Minakshi; Khadwal, Alka Rani; Bal, Amanjit; Das, Reena; Varma, Neelam
• Is Part Of: Tropical medicine & international health. Volume 26:Issue 4(2021)
• Page Start: 462
• Page End: 468
• Publication Date: 2021-02-02
• Subjects: erythrocytes -- flow cytometry -- G6PD -- heterozygous female carriers -- laboratory diagnosis; Tropical medicine -- Periodicals; Public health -- Periodicals; 616.988
• DOI: 10.1111/tmi.13547
• Languages: English
• ISSNs: 1360-2276

Abstract

Abstract: Objective: Glucose‐6‐phosphate dehydrogenase (G6PD) deficiency, an X‐linked recessive disorder, is the commonest erythrocytic enzymopathy worldwide. Reliable diagnosis and severity prediction in G6PD‐deficient/heterozygous females remain challenging. A recently developed flow cytometric test for G6PD deficiency has shown promise in precisely identifying deficient females. This paper presents our experiences with this test in a subtropical setting and presents a modification in flow cytometric data acquisition strategy. Methods: The methaemoglobin reduction + ferryl Hb generation‐based flow cytometric G6PD test was compared with the screening methaemoglobin reduction test (MRT) and confirmatory G6PD enzyme activity assay (EAA) in 20 G6PD‐deficient males, 22 G6PD‐heterozygous/deficient females and 20 controls. Stained cells were also assessed for bright/dim G6PD activity under a fluorescent microscope. Results: Flow cytometry separated and quantified %bright cells in heterozygous/deficient females, objectively classifying them into 6 normal (>85% bright cells), 14 intermediate (10‐85%) and two G6PD‐deficient (<10% bright cells). Concordance with MRT was 89% (55/62 cases) and with EAA was 77% (48/62 cases). Fluorometrically predicted violet laser excitation (405‐nm) with signal acquisition in the 425–475 nm region was a technical advancement noted for the first time in this paper. Conclusion: Flow cytometry/fluorescence microscopy represent technically straightforward methods for the detection and quantification of G6PD‐deficient erythrocytes. Based on our results, we recommend their application as a first‐line investigation to screen females who are prescribed an oxidant drug like primaquine or dapsone.