Abstract
A modification is proposed for the conventional pH stat assay for human plasma and erythrocyte cholinesterases. Principal advantages for the micromodification are smaller sample size afforded by collection of specimens in microhematocrit tubes and reduction in subsequent sample-handling time. Red blood cell (RBC) washing and recentrifugation steps are eliminated. Although the basic assay procedure remains unchanged, titration parameters are changed to accommodate smaller sample volumes. Results from either assay procedure are comparable, as shown by statistically significant regressions of micromodification assay data upon those of conventional pH stat procedure.