[Study of the stability and the degradation of fluorescence in the immunofluorescence technic (FTA-ABS) using pulsed...

The use of two pulsed lasers as excitation sources in the immunofluorescent technique FTA-ABS (fluorescent treponemal antibody absorption) shows that excitation of specimens by continuous or long-duration pulses of light (in the order of a millisecond) degrades the fluorescence in such a way that it is impossible to quantify exactly the fluorescent signal or repeat the analysis. Stability of fluorescence can be achieved by very short excitation pulses (in the order of a microsecond) and this fast fluorescent signal can be detected only by an electronic detection and recording system. With such a system, high precision is obtained by elimination of errors by the human eye.