2020 Volume 69 Issue 4 Pages 570-576
The lactate dehydrogenase (LD) activity test was converted from the JSCC method to the IFCC method on 1 April 2020. We conducted a basic evaluation of LD activity using “L-type Wako LD·IF” manufactured by Fujifilm-Wako. Parallel-run precision and reproducibility for all control materials were good with a C.V. below 1.2%. The detection limit determined using 10 dilution series of high-activity LD samples was 2,470 U/L. There was no interference by bilirubin F, bilirubin C or chyle, but hemoglobin caused a false positive result. The correlation between currently used reagents was good with similar results, that is, correlation factor r = 0.994 and regression equation y = 0.923x + 9.8. Isozyme analyses of five samples using “Quick Gel LD” manufactured by Helena showed a small divergence from the regression line and indicated that the LD5 fraction was over 59%, which means that the M subunit was dominant in the five samples. The normal LD activity range was calculated as 108–202 U/L. The results showed that L-type Wako LD·IF reagent has sufficient performance for routine testing.
