Sensitivity, precision, and accuracy of the Y1 adrenal cell enterotoxin assay

The Y1 adrenal cell assay for heat-labile enterotoxin (LT) was found to be relatively insensitive for filtrates of toxigenic Escherichia coli H10407. When observations were made blindly and subjected to rigorous controls, reliable detection of LT occured only at filtrate dilutions from 1:4 to 1:10. Detection of LT was unreliable when E. coli H10407 was mixed with another enteric organism. Overall, 7.1% of observers' reports from a single assay were imprecise, and 2.6% would have resulted in errors in detection of LT; however, triplicate assays prevented false positive reports of LT detection. Routine testing for LT production in the clinical diagnostic laboratory awaits a simpler, more sensitive, and more direct method of testing stool specimens.