Evaluation of Treponema pallidum antibody test in blood donors

Lee, Chung Young; Han, Sang Moo; Kang, Kwon Chul

Abstract

BACKGROUND
Current serologic tests for Syphilis(STS) in the blood donors are Veneral Disease Reseach Laboratory(VDRL), Rapid Plasma Reagin(RPR) test or Groupamatic Automated Syphilis Test(GAST) using modified VDRL antigen as screening method, and Treponema Pallidum Hemagglutination(TPHA) test as a confirmatory method in Korean Red Cross Blood Centers. This study was carried out to evaluate the usefulness of Enzyme Immunoassay(EIA) as STS in blood donors.
METHODS
A total of 11,335 donors s serum samples were tested by RPR and GAST. We analyzed 138 samples including 6 samples of anti-treponema pallidum panel with TPHA and EIA to compare as a confirmatory test.
RESULTS
The positive rate of RPR and GAST in 11,335 samples were 0.68%, 0.24%, respectively. Confirmed positive rates by TPHA was 0.26%, and by EIA was 0.27%. False negative results of GAST were 0.11% and 0.13%, respectively according to the results of TPHA and EIA. The agreement between TPHA and EIA was 98.5%(130/132).
CONCLUSION
The EIA results were comparable with RPR, GAST and TPHA test. It is considered that EIA method for STS would be alternative one for TPHA as a conformative test because there was excellent agreement between TPHA and EIA method, and EIA method showed almost same results as that of TPHA test.