Table 2

Syphilis rapid tests results on serum and fingerprick blood among CLIA and TPPA-positive individuals: RPR-positive (part A, 16 samples), RPR-negative (part B, 19 samples)

Laboratory reference method resultTitresSyphilis history T pallidum RDTs result on serum* T pallidum RDTs result on blood*
IDCLIATPPARPRTPPARPRSD BiolineChembio TChembio NTSD BiolineChembio TChembio NT
Reader 1Reader 2Reader 1Reader 2Reader 1Reader 2Reader 1Reader 2Reader 1Reader 2Reader 1Reader 2
Part A (RPR-positive)1+++20 480128PosRRRRRRRRRRRR
2+++20 480128NegRRRRRRRRRRRR
3+++20 48032NegRRRRRRRRRRRR
4+++20 48016NegRR....NRR....
5+++10 24016PosRR....RR....
6+++512016NegRR....RR....
7+++20 48016NegRRRRRRRRRRRR
8+++20 4808PosRRRRRRRRRRRR
9+++10 2408NegRRRRRRRRRRRR
10+++20 4804PosRRRRNRNRRRRRNRNR
11+++20 4804NegRRRRNRNRRRRRNRNR
12+++51204NegRRRRRRRRRRRR
13+++51202NegRR....NRNR....
14+++20 4802NegRRRRNRNRRRRRNRNR
15+++10 2401PosRR....RR....
16+++10 2401PosRR....RR....
Part B (RPR-negative)1++–10 2400PosRRRRNRNRRRRRNRNR
2++–10 2400PosRRRRNRNRRRRRNRNR
3++–51200NegNRNRNRNRNRNRNRNRNRNRNRNR
4++–51200PosRR....NRNR....
5++–25600PosRRRRNRNRRRRRNRNR
6++–12800PosNRRNRRNRRNRNRRRNRNR
7++–12800PosNRNRNRNRNRNRNRNRNRNRNRNR
8++–6400PosRRRRNRNRNRNRRRNRNR
9++–6400NegNRNRNRNRNRNRNRNRNRNRNRNR
10++–6400PosRRNR.NR.RNRRRNRNR
11++–6400NegRR....NRNR....
12++–6400PosRRNRNRNRNRNRNRNRNRNRNR
13++–3200PosRR....NRNR....
14++–3200NegRRRRNRNRNRNRNRNRNRNR
15++–1600PosRRNRNRNRNRNRRNRRNRNR
16++–1600PosNRNRNRNRNRNRNRNRNRNRNRNR
17++–1600PosRRNRNRNRNRNRNRNRNRNRNR
18++–800NegNRNRNRNRNRNRNRNRRRNRNR
19++–800PosNRNRNRNRNRNRNRNRNRNRNRNR

  • * Grey boxes indicate discordant results between RDT and reference test.

  • ‘.’ indicates missing test (Chembio DPP Syphilis Screen & Confirm Assay expired during the study, therefore they were used only in a subsample of men who have sex with men).

  • Neg, negative; NT, non-treponemal test; NR, no reactive; Pos, positive; R, reactive, RDTs, rapid diagnostic tests; T, treponemal test.