Study on Rpcf and Fta: Comparison of Serological Reactions for Syphilis

Abstract

Comparison was carried out of two distinct types of serological procedures currently in use for the diagnosis of syphilis:(1) the procedures using cardiolipin antigan, viz. Ogata's complement fixation reaction, agglutination reaction and VDRL, and (2) those using Treponema Pallidum as antigen, viz. RPCF and FTA, in respect of sensitivity and biological false positivity.
Sera tested were taken from patients and suspected persons with syphilis, pregnant women, and cancer patients.
Results were as follows:
1. Percentage of sccordance between results obtained by cardiolipin (CL) and Treponema Pallidumt (TP) methodds was 83-86, while between those by FTA and RPCF was 95.3. The comparatively high parallelism between two methods using TP antigen, so FTA and RPCF were considered to be due to the common antigenic constituents contained in them.
2. Of CL-positive sera from cancer patients, cases to be considered to be bilogocial false positive by chequing with case history, clinical findings, and TP-methods, were 27 (62.8%). Of 23 sera showing positive RPCF, 7 (25.9%) were similarly interpreted to be biological false positive. Of 16 (37.2%) proved to be positive by FTA, noce was thought to be biological false posititve, so FTA seems to be the method of choice in specificity for sypjilis diagnosis.
3. Negative conversion of the sera from patients after antisyphilitic treatment was observed earlier in FTA and RPCF than in the CL methods, this is indicating the importance of the two methods as index of the effect of antisyphilitic therapies.