Evaluation of a solid-phase enzyme immunoassay in the diagnosis of syphilis

Abstract

A solid phase enzyme-linked immuno sorbent assay (ELISA), the antigen being bound to the surface of ferrous metal beads, was evaluated as either a diagnostic or a confirmative test for syphilis by comparison with the Venereal Disease Research Laboratory (VDRL) and the fluorescent treponemal antibody absorption (FTA-abs) tests in two groups of` population: healthy people and syphilitic patients. The sensitivity of the ELISA test was found to be 75%, the specificity 98.1%. There were no statistically significant differences as to accuracy (sensitivity and specificity) between ELISA test and the VDRL test (p<0.05). The ELISA test therefore does not represent an improvement in the first line syphilis diagnosis when compared with the classical VDRL test. ELISA was less reactive than the FTA-abs test in all the stages of the disease. Its only advantage is easier performance by automation.