Italian National Survey of Blood Donors: External Quality Assessment (EQA) of Syphilis Testing

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. 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.

Prevalence of syphilis among voluntary blood donors in Liguria region (Italy) from 2009 to 2013

“…In agreement with the authors who performed an external assessment of the quality of other Italian transfusion services, 7 we recommend the use of two distinct treponemal and nontreponemal tests, since the non-treponemal test is the least sensitive means of identifying syphilis-positive samples. 7 International Journal of Infectious Diseases 28 (2014) 45-46 …”

Confirmation of High Specificity of an Automated Enzyme Immunoassay Test for Serological Diagnosis of Syphilis

“…The T. pallidum hemagglutination assay and FTA-Abs were both positive in 53% of these samples. [13][14][15] As shown in Table 2, even with the same test results, it is not always easy to come to a final conclusion. The current version of the assay (3.0) was recently evaluated by Donkers et al 8 in 1251 samples (syphilis prevalence 8.0%), and they found an agreement of 100% with the other 2 EIAs used in their study.…”

“…In our previous evaluation, however, the Bioelisa did not miss any positive sample. [9][10][11][12][13] Another interesting point in the study by Castro et al, 9 mentioned previously, is that they question the use of the FTA-Abs as a confirmatory assay based on their results because it was the least sensitive. The T. pallidum hemagglutination assay and FTA-Abs were both positive in 53% of these samples.…”

Efforts in blood safety: Integrated approach for serological diagnosis of syphilis

“…[ 59 ] This contributes to generate high discrepancies both in clinical laboratories and in blood transfusion centers stressing the need to generate an efficient algorithm. [ 60 ]…”