Validating the Assessment of Glucose-6-Phosphate Dehydrogenase (G6PD)

Charles Asowata Major; Emily Fincher; Vernon Koziatek; Lester Pretlow

doi:10.29074/ascls.19.3.134

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Charles Asowata Major, MS MT(AMT) CLS(NCA)
Emily Fincher, MS MT(ASCP)
Vernon Koziatek, BS CLS(NCA)

are of the Dwight D Eisenhower Army Medical Center, Fort Gordon GA

Lester Pretlow, PhD CLS(C) NRCC(CC)⇑
1. is of the Department of Biomedical and Radiological Technologies, Medical College of Georgia, Augusta GA

Address for correspondence: Lester G Pretlow PhD CLS(C) NRCC(CC), Assistant Professor, Department of Biomedical and Radiological Technologies, AL-106, Medical College of Georgia, Augusta GA 30912-0500. (706) 721-7629, (706) 721-7631 (fax). lpretlow{at}mail.mcg.edu

Extract

Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme of clinical significance to the Armed Services. The ability to determine accurate erythrocyte concentrations of G6PD is imperative for the prophylaxis and treatment of service members against a variety of opportunistic hemolytic infectious diseases, such as malaria, which might be encountered during deployment.¹ G6PD catalyzes the first oxidation reaction in the pentose phosphate shunt, in which glucose-6-phosphate is dehydrogenated to 6-phosphogluconolactone with the concurrent reduction of nicotinamide adenine dinucleotide phosphate (NADP).² This reaction is the only source of the reduced form of NADP, NADPH, which provides the reducing power to change oxidized-glutathione into reduced-glutathione.³ Reduced glutathione acts as a reducing agent against oxidative insults to the erythrocyte.

G6PD deficiency is expressed when individuals with decreased reduced-glutathione concentrations are administered oxidant drugs such as quinine, analgesics, and sulfonamides.³ The decrease in reduced-glutathione leads to the inability of erythrocytes of these individuals to endure the oxidative assault of these drugs. As a consequence, erythrocytes lose their structural integrity, resulting in hemolytic anemia that can be moderate to life threatening. G6PD deficiency is the most widely distributed enzyme defect of erythrocytes in humans, therefore, it is important to screen all service members for the enzyme deficiency before they are prophylaxed in preparation for deployment.⁴ This potential for drug induced hemolytic complications demands screening and for that reason, the analytical procedures for assessing G6PD concentrations must be rigorously validated to ensure the best quantitative determinations.⁵ Most methods for the analysis of G6PD are based on the assessment of…

ABBREVIATIONS: CAP = College of American Pathologists; E_A = allowable error; G6PD = Glucose-6-phosphate dehydrogenase; MDC = medical decision chart; MDL = medical decision level; NADP = nicotinamide adenine dinucleotide phosphate; R_E = random error; SD = standard deviation; S_E = systemic error.