Detection of biological false positive syphilis serum reactions
A comparative evaluation of reagin tests (Wassermann, VDRL, RPR) and fluorescent treponema antibody absorption tests (FTA ABS) performed on blood specimens from 5,271 persons (2,493 pregnant women, 1,130 apparently healthy prospective employees, 1,345 newborn babies and 303 leprosy patients) showed that 17.2% of the pregnant women, 11.95% of the prospective employees, 19.0% of the newborn babies, and 27.2% of the leprosy patients gave positive reactions in one or more of the tests. The majority of specimens were from Cape Colored patients. FTA ABS tests allowed the exclusion as biological false positives of ± 30% of the pregnant 'positive reactors', of ± 37% of the prospective employees, 40.2% of the newborn babies, but only 1% of the leprosy patients. The FTA ABS test, therefore, deserves wide acceptance as the standard by which the diagnosis of syphilis is confirmed and false positive reactions are defined, although non specificity in pregnancies, intracellular infections and auto immune diseases occurs. The classical reagin tests are of value in the control of treatment.