Components of variability in blood cholinesterase assay results.
Yager-J; McLean-H; Hudes-M; Spear-RC
J Occup Med 1976 Apr; 18(4):242-244
In order to test the adequacy of blood cholinesterase (9001085) as an index of human response to organophosphate pesticide exposure, an experiment is described in which commercially available control sera are evaluated as a laboratory standard, based on the concept that the plasma cholinesterase activity in the control sera is constant over time and that the daily variations observed in the activity of the enzyme would then be attributable to laboratory related factors. The removal of this component of the variance from the activity determined from blood samples drawn from human volunteers would then reveal the amount of the overall variance attributable to the individual donor plus the uncontrolled residual variance. Another important assumption tested is that those factors responsible for day-to-day variance of the activity of plasma enzyme are also responsible for the daily variance in the activity of the red blood cell enzymes. It is shown that the commercially available sera cannot serve as controls for red blood cell enzyme or in controlling the variability in plasma enzyme assays. The proportion of the total variability attributable to laboratory changes is about 40 percent.
JOCMA7; NIOSH-Publication; NIOSH-Contract; Contract-099-74-0110; Toxic-substances; Blood-chemistry; Organo-phosphorus-insecticides; Analytical-methods; Blood-analysis; Serum-enzymes; Enzyme-activity; Serology; Monitoring
Journal of Occupational Medicine