A Comparative Study of the VDRL and FTA-ABS Tests in Korea

ABSTRACT

During the period from January to December 1976, 12,489 VDRL (Venereal Disease Research Laboratory) and 2,965 FTA-ABS (Fluorescent Treponemal Antibody Absorption) tests were made. The reactive VDRL tests represented 3.6% of the total tested and the reactive rate of the FTA-ABS was 17.4%. The reactive VDRL and FTA-ABS tests represented 422 patients with clinically known diseases. The purpose of this study was to correlate the serologic findings with clinical problems. We divided the patients into three groups 1. those with clinically diagnosed syphilis, 2. those with a history or physical findings compatible with syphilis, 3. those with no clinical evidence of syphilis. In groups 1 and 2, which represented 27% and 36.7%, respectively, a close correlation occurred between the two tests, both being reactive in 93-98% of the patients. However the VDRL was more informative than the FTA-ABS in determining clinical stages. In group 3, representing 36.3% of the reactive tests, the agreement between the two tests dropped to 77%; the FTA-ABS test was reactive in an additional 32 cases, 21% more than the VDRL. These discrepancies may well be due to the greater sensitivity of the FTA-ABS test in very early or late syphilis when there are no clinically recognizable manifestations. However the possibility of false positive FTA-ABS reactions could not be ruled out.