Abstract
Because of conflicting views concerning the stability of plasma cbolinesterase and red cell acetylcholinesterase in stored samples, these activities were measured in sample stores at temperature ranging from −20° to 55 °C. The results showed both enzymes to be stable for years if kept at ambient temperatures or lower, unless the enzymes were destroyed by bacterial contamination. Stoppering and sealing of sample vials, and use of chloromycetin were investigated. Inhomogeneity in stored samples could give an, apparent loss of activity. Rate of activity loss was slow but progressive at 37°; correspondingly more rapid and also two-stage at 45° and 55°. Pre-storage aliquotting is indicated where sample dilution is not feasible.