Application of quantitative immunofluorescence to clinical serology: antibody levels of Treponema pallidum.

A previously reported method of quantitative immunofluorescence, employing a calibrated photometric system and chemically stabilized fluorescence intensity, was used to replace the subjective, visual method of endpoint determination with a quantitative, calibrated measurement of antibodies to Treponema pallidum in serum. The results of the quantitative immunofluorescence method showed a 90% correlation with the subjective determinations of the visual method.