Absence of risk factors for false-positive test results in blood donors with a reactive test result in an automated treponemal test (PK-TP) for syphilis.

Abstract

BACKGROUND:

Screening and confirmatory serologic tests for syphilis are known to generate false-positive results in low-risk populations, which include blood donors. This study assessed whether conditions previously reported to cause biological false-positive (BFP) test results for syphilis are relevant to contemporary syphilis testing of blood donors and the extent to which seropositive donors report a history of syphilis.

STUDY DESIGN AND METHODS:

A history of conditions reported to be associated with BFP syphilis tests or a history of syphilis infection was assessed by a case-control study of donors with reactive and nonreactive automated treponemal test results, using an anonymous mail survey. Analysis of cases was stratified by fluorescent treponemal antibody absorption (FTA-ABS) result.

RESULTS:

Adjusted ORs (95% CIs) for reported BFP-associated conditions were 1.3 (0.8-2.1) for FTA-ABS-positive cases and 0.8 (0.3-1.9) for FTA-ABS-negative cases. Among responding blood donors, syphilis history was reported in 78 (51%) of 153 FTA-ABS-positive cases, 0 of 142 FTA-ABS-negative cases, and 3 (0.4%) of 716 automated treponemal test (PK-TP)-negative controls.

CONCLUSION:

Approximately half of donors with FTA-ABS-positive test results reported a syphilis history. There was no difference between reported BFP conditions for FTA-ABS-positive or FTA-ABS-negative cases and controls. This information may be useful when providing donors with better predonation or post-test counseling information about syphilis testing.

• Authors: S L Orton, R Y Dodd, A E Williams, ARCNET Epidemiology Group. American Red Cross
• Journal: Transfusion (Transfusion) Vol. 41 Issue 6 Pg. 744-50 (Jun 2001) ISSN: 0041-1132 [Print] United States
• PMID: 11399813 (Publication Type: Journal Article)

Topics

• Adolescent
• Adult
• Blood Donors
• False Positive Reactions
• Female
• Humans
• Male
• Middle Aged
• Risk Factors
• Syphilis (diagnosis, prevention & control, transmission)
• Transfusion Reaction
• Treponema Immobilization Test