Automated determination of glucose-6-phosphate dehydrogenase (G6PD) on a SPOTCHECK Microflow analyzer.

ABSTRACT

Glucose-6-phosphate dehydrogenase (G6PD) is the initial enzyme in the hexose monophosphate pathway of glucose metabolism. Deficiency of G6PD has been linked to increased sensitivity of red cells to hemolytic anemia due to certain oxidant drugs, infectious agents or fava beans. It is an inherited error in metabolism and has a high incidence in certain ethnic groups. Astoria-Pacific has developed an automated assay for use on the SPOTCHECK Microflow Analyzer for the semi-quantitative determination of G6PD activity in erythrocytes. After sample extraction, all assay steps are automated including reagent addition, incubation and data collection. Use of on-line dialysis removes interferences. The assay is intended primarily as a screening tool in the diagnosis and treatment of disease states associated with G6PD deficiency in newborns. G6PD in the dried blood spot is extracted and placed on the instrument. Samples are then aspirated into the system at a rate of 90 samples/hour. All other reagents are added by the SPOTCHECK Analyzer on-line during sample processing. Incubation of each sample occurs on-line at 37 degrees C, and after dialysis the NADPH reaction product is excited at 365 nm. Fluorescence is measured at 500 nm. A lack of fluorescence indicates a probable G6PD deficiency. Data reduction occurs real time through a FASPac software thus individual results are available during a run as soon as each sample analysis is complete. The Astoria-Pacific International G6PD reagent kit paired with the SPOTCHECK Microflow Analyzer provides an effective and easy to use screening tool for determining G6PD deficiency in newborns.