Table 1. Laboratory syphilis tests
Characteristic Patients tested n =52 055Syphilis diagnoses n = 522 (positivity %) Laboratory tests n =67 953Positive laboratory tests n =6503
Sex
Male28 090 (54.0)501 (1.8)39 060 (57.5)5591 (14.3)
Female23 963 (46.0)21 (0.1)28 891 (42.5)912 (3.2)
Missing data2020
Age years, a median ( IQR ) 34 (27–44)44 (35–52)
<15132 (0.3)0151 (0.2)0
15–258478 (16.3)33 (0.4)9881 (14.5)262 (2.7)
26–3520 549 (39.5)103 (0.5)25 074 (36.9)951 (3.8)
36–4511 641 (22.4)156 (1.3)15 393 (22.7)1649 (10.7)
46–557031 (13.5)153 (2.2)10 630 (15.6)2050 (19.3)
>554213 (8.1)77 (1.8)6824 (10.0)1591 (23.3)
PCR N/AN/A617 (0.9)106 (17.2)
Anti- T. Pallidum ( EIA ) N/AN/A46 389 (68.3)3095 (6.7)
Positive in the pastb N/AN/AN/A1303 (42.1)
New positivec N/AN/AN/A85 (2.7)
TPHA/TPPA N/AN/A17 125 (25.2)1842 (10.8)
Positive in the pastb N/AN/AN/A607 (33.0)
New positivec N/AN/AN/A30 (1.6)
Confirmation (immunoblot)N/AN/A1042 (1.5)926 (88.9)
VDRL/RPR (positive ≥1:4)N/AN/A2780 (4.1)534 (19.2)
  • aAge in years at first test for patients’ column, age at test for other columns. bSome laboratories reported laboratory tests as 'positive in the past', even though it was the first lab request in this patient during the studied period. c New positive after an earlier negative test.

  • EIA = enzyme immunoassay. IQR = interquartile range. N/A = not applicable. PCR = polymerase chain reaction. RPR = rapid plasma reagin. TPHA/TPPA = Treponema pallidum haemagglutination assay/T. pallidum particle agglutination assay.VDRL = venereal disease research laboratory.