Italian national survey of blood donors: External Quality Assessment (EQA) of syphilis testing

Francesca Vulcano, Luisa Milazzo, Sabrina Volpi, Mara Maria Battista, Alessandra Barca, Hamisa Jane Hassan, Fulvia Pimpinelli, Adele Giampaolo

Research output: Contribution to journalArticlepeer-review

Abstract

The detection of syphilis among blood donors may reveal high-risk sexual behavior, which can go unreported at the time of donor selection and compromise the safety of the donated blood. In Italy, blood is collected, tested, and distributed by transfusion services (TSs), which also perform outpatient transfusions. Although the TSs must screen for syphilis by law, there are no indications of the specific type of method to be used, generating discrepancies in the results obtained by the different TSs. To determine the proficiency of the TSs in screening for syphilis, we performed an external quality assessment (EQA). The EQA was based on two shipments of serum panels; 133 and 118 of the 326 existing TSs participated in the first and second shipments, respectively. Each panel consisted of both positive and negative serum samples. The results confirmed that the use of a single nontreponemal test (the Venereal Disease Research Laboratory [VDRL] and the rapid plasma reagin [RPR] tests) is the least sensitive means of identifying samples that are positive for syphilis antibodies. We also found that the interpretation of the results of manual techniques, such as the RPR test, the VDRL test, the Treponema pallidum hemagglutination (TPHA) assay, and the T. pallidum particle agglutination (TPPA) assay, can vary greatly among different TSs and operators. Total Ig enzyme immunoassays (EIAs) are the most sensitive. However, the determination of syphilis on the basis of the results of a single test is not sufficient for an accurate screening; and all blood units should thus be assessed by two distinct treponemal tests, that is, a total Ig EIA and the TPHA or the TPPA assay.

Original languageEnglish
Pages (from-to)753-757
Number of pages5
JournalJournal of Clinical Microbiology
Volume48
Issue number3
DOIs
Publication statusPublished - Mar 2010

ASJC Scopus subject areas

  • Microbiology (medical)

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