Laboratory and field microassay of cholinesterases in whole blood, plasma, and erythrocytes.

A straightforward method is described for determination of the activities of erythrocyte acetylcholinesterase and plasma cholinesterase from single 10-mul samples of highly diluted whole blood. The procedure is a spectrophotometric microassay adapted for use with microtitration plates. The use of an enzyme immunoassay reader facilitates the rapid analysis of large numbers of samples. An inexpensive adaptation of the method was also devised that requires no instrumentation and was evaluated under field conditions in Haiti. Either the field or laboratory versions of the method can accurately determine increments of 10% or less in the level of inhibition of acetylcholinesterase or cholinesterase in whole blood, plasma, or erythrocytes.