Statistical approach to evaluating the method of Morgan and Vryonis for enumerating Treponema pallidum.

The contributions of four components to the error in the microscopic enumeration of spirochetes (Treponema pallidum) by the method of Morgan and Vryonis were determined. Where N(s) = the number of slides counted, N(r) = the number of recounts of 50 fields per slide, N(p) = the number of pipettes used, and N(e) = the total number of counts of 50 fields made, the coefficient of variation is 2 times the square root of (17.5(2)/N(s) + 18.6(2)/N(r) + 14.8(2)/N(p) + 6.1(2)/N(e)) with 95% confidence.