Effect of storage on bovine erythrocyte cholinesterase activity.

: Bovine whole blood and washed erythrocyte samples with either sodium heparin or EDTA as the anticoagulant were stored at -24, 2 to 3, 21, or 37 C for up to 8 weeks to determine the stability of erythrocyte cholinesterase (ChE) activity. An automated colorimetric method was used to measure ChE activity. Regression analysis was used to estimate the rate of decline of ChE activity of samples to 95% of normal. Samples stored at -24 and 2 to 3 C were very stable, and ChE activity was maintained for several weeks or longer. Samples stored at 21 C maintained an activity level not less than 95% of normal for at least 9 days and those stored at 37 C for at least 2 days. The type of anticoagulant used did not appear to affect significantly the stability of activity.