2.2. Quantitation of G-6-PD activity
Red cell G-6-PD activity was measured by a quantitative kinetic method using a commercial kit (Trinity Biotech USA, Jamestown, NY, USA) and an automated analyzer (Synchron CX-4; Beckman Coulter, Inc). In brief, 15 μl aliquot of whole blood was added to 135 μl of lysing reagent and vortexed. The lysate was used then for determining G-6-PD activity,measured at 37 °C as the rate of increase in NADPH absorbance at 340 nm. G-6-PD activity is expressed as U/g Hb. Hb concentration of the lysate was determined by the Synchron CX4 analyzer. The manufacturer's reference value for normal G-6-PD activity is 7.0–20.5 U/g Hb. Samples with G-6-PD activity b 7.0 U/g Hb were classified as G-6-PD deficient. Reliability of the resultswas monitored using 2 different controls provided by themanufacturer (intermediate and normal
level) with each run. Runs are considered valid if control values fell within the given rang