Comparative evaluation of enzyme-linked immunosorbent assay with rapid plasma reagin for screening of syphilis in blood donors

Abstract

World Health Organization (WHO) recommends screening of syphilis in low prevalence populations of blood donors by treponemal tests like enzyme-linked immunosorbent assay (ELISA), whereas in India screening is done by rapid plasma reagin (RPR). The present pilot study evaluated the performance of ELISA compared to RPR, keeping Treponema pallidum hemagglutination assay as a reference test. ELISA was equally sensitive (100%), more specific (56.3% vs. 0%), more accurate (83.7% vs. 62.7%), had better positive predictive value (79.4% vs. 62.8%) and negative predictive value (100% vs. 0%), and less biological false positivity (37.2% vs. 20.6%) when compared to RPR. The WHO recommendations of screening for syphilis in low prevalence population of blood donors using ELISA may be adopted for usage in transfusion services that have the facility of ELISA.

Keywords

• Biological false positivity
• enzyme-linked immunosorbent assay
• negative predictive value
• positive predictive value
• rapid plasma reagin
• syphilis
• Treponema pallidum hemagglutination assay
• Venereal Disease Research Laboratory