Determining cholinesterase activity in human plasma. Simple test-strip method.

Abstract

NUMEROUS titrametric, manometric, colorimetric, and electrometric methods of determining the activity of cholinesterase (ChE) have been reported.¹Among these quantitative measurements, the electrometric method of Michel²and the colorimetric method of de la Huerga et al³are the most widely used. Simpler methods based upon the change of color of suitable indicators have been reported.^4,5However, all of these require facilities which are not usually available in the average clinical laboratory. Limperos and Ranta⁶described a semiquantitative method of determining ChE in the whole blood by observing the color change of bromothymol blue. This was modified and adapted for use as a screening test.^{7, 8}Herzfeld and Stumpf⁹reported on a test-paper method, the results of which were recently demonstrated by other investigators to be in reasonably good agreement with results obtained by the manometric and the electrometric methods.^{10, 11}This ChE