TABLE 2

Specificities of the Elecsys syphilis assay using lot A and specificities of comparator assays

Result by sample typeElecsys syphilis assay lot AArchitect syphilis TP assayLIAISON Treponema screenSerodia-TPPAVitros syphilis TPAEnzygnost syphilis assayImmulite 2000 syphilis screen
Routine samples
    Total no. tested3,5001,5003,5001,5002,000
    No. confirmed positive14114113
    No. indeterminate00000
    No. negative3,4861,4993,4861,4991,987
    No. false positive751220
    Specificity (% [2-sided 95% CI])a99.80 (99.59–99.92)99.67 (99.22–99.89)99.66 (99.40–99.82)99.87 (99.52–99.98)100.00 (99.81–100.00)
Blood donor samples
    Total no. tested4,5793,0061,5741,5061,574
    No. confirmed positive00000
    No. indeterminate2b2b01b0
    No. negative4,5773,0041,5741,5051,574
    No. false positive38030
    Specificity (% [2-sided 95% CI])99.93 (99.81–99.99)99.73 (99.48–99.88)100.00 (99.77–100.00)99.80 (99.42–99.46)100.00 (99.77–100.00)
Total samples
    Total no. tested8,0794,5063,5001,5001,5741,5063,574
    No. confirmed positive1411410013
    No. indeterminate2b2b0001b0
    No. negative8,0634,5033,4861,4991,5741,5053,561
    No. false positive1013122030
    Specificity (% [2-sided 95% CI])99.88 (99.77–99.94)99.71 (99.51–99.85)99.66 (99.40–99.82)99.87 (99.52–99.98)100.00 (99.77–100.00)99.80 (99.42–99.96)100.00 (99.90–100.00)
  • a CI, confidence interval.

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