Zastosowanie testu Syphilis Total Ab na aparacie Evolis (firmy BIO-RAD) do prowadzenia badań przeglądowych w krwiodawstwie

Background: Syphilis Total Ab BIO-RAD (France) is designed for detection of antibodies to Treponemapallidum antigens in human serum and plasma. Tests are performed in automatic analyzers Evolis (BIORAD). The aim was to evaluate the advantages of the Syphilis Total Ab BIO-RADtest for blood donor screening in Poland. Specificity, sensitivity, repeatability and reproducibility of S/Co values were evaluated. After 18 months of using the test at the Military Blood Center (WCKiK), the results were analyzed and compared to those obtained with other EIA tests which had been in use for 36 months before the implementation of Syphilis Total Ab BIO-RAD. Material and methods: Specificity evaluation was performed at the Institute Hematology and Transfusion Medicine (IHiT) on samples collected from 2058 currently screened donors. Assessment of clinical sensitivity was based on study outcome of: 1) seropositive sample panels (confirmed), raw and prepared by dilution of positive archive serum, 2) seroconversion panel (SeraCare), 3) samples reactive in a prospective study performed for assessment of test specificity. Additionally, we analyzed results for 48 940 donations tested with Syphilis Total Ab BIO-RAD between January 2015 and June 2016 and the results were compared with results for 89.672 donations tested in the period 2012–2014 with Trepanostika TP rec. bioMerieux (France). Results: Specificity of Syphilis Total Ab BIO-RAD test is equal to 99.9%; repeat reactive (RR) samples with indeterminate confirmation results were considered false reactive. In our own panel studies all samples were found reactive both in the evaluated assay and in reference test (100% compliance). The same number of reactive results was reported for both tests in seroconversion panel studies. Frequency of confirmed RR results in the period 2012–2016 at WCKiK was calculated at 0.0079% (11/138,612 donations). Specificity of Syphilis Ab BIO-RAD was equal to 99.98% as compared to 99.79% reported for the period before test implementation and the positive predictive value of the evaluated test was significantly higher (40% vs. 2.65%, p < 0.05). Conclusions: The S/Co values for specificity, sensitivity, reproducibility and repeatability of Syphilis Total Ab Test BIO-RAD performed on the analyzer Evolis were found satisfactory. The study outcome demonstrates that the choice of a higher-specificity test (positive predictive values) brings about measurable cost-cutting (smaller number of repeat, verification and control tests performed as well as reduced blood component wastage) and reduction in number of temporarily disqualified donors.