Specificities of the Elecsys syphilis assay using lots B and C and specificities of comparator assays

Result by sample typeElecsys syphilis assay lot BElecsys syphilis assay lot CArchitect Syphilis TP assayLIAISON Treponema screenEnzygnost syphilis assay
Routine samples
    Labor Schottdorf, Germany
        Total no. tested1,0001,0001,000
        No. confirmed positive111
        No. indeterminate1b1b1b
        No. negative998998998
        No. false positive100
        Specificity (% [2-sided 95% CI])a99.90 (99.44–100.00)100.00 (99.63–100.00)100.00 (99.63–100.00)
Blood donor samples
    Central Institute for Blood Transfusion and Immunology, Austria
        Total no. tested1,0491,0491,049
        No. confirmed positive000
        No. indeterminate000
        No. negative1,0491,0491,049
        No. false positive000
        Specificity (% [2-sided 95% CI])100.00 (99.65–100.00)100.00 (99.65–100.00)100.00 (99.65–100.00)
    Ege University, Turkey
        Total no. tested632632632
        No. confirmed positive111
        No. indeterminate000
        No. negative631631631
        No. false positive335
        Specificity (% [2-sided 95% CI])99.52 (98.62–99.90)99.52 (98.62–99.90)99.21 (98.16–99.74)
    Overall blood donor specificity (% [2-sided 95% CI])99.82 (99.48–99.96)99.82 (99.48–99.96)99.21 (98.16–99.74)100.00 (99.65–100.00)
Overall specificity (% [2-sided 95% CI])99.85 (99.62–99.96)99.89 (99.67–99.98)99.21 (98.16–99.74)100.00 (99.63–100.00)100.00 (99.65–100.00)
  • a CI, confidence interval.

  • b Excluded from the specificity calculation due to indeterminate confirmation results.