Volume 29, Number 8—August 2023
Research Letter
Rapid Serologic Test for Diagnosis of Yaws in Patients with Suspicious Skin Ulcers
Table
Performance of DPP Syphilis Screen & Confirm kit in study of rapid serologic test for diagnosis of yaws in patients with suspicious skin ulcers
Detection technique |
PCR negative |
Specificity, % (95% CI) |
PCR positive |
Sensitivity, % (95% CI) |
Sensitivity + specificity, % |
PPV, % (95% CI) |
NPV, % (95% CI) |
||
---|---|---|---|---|---|---|---|---|---|
Detected, no. |
Not detected, no. |
Detected, no. |
Not detected, no. |
||||||
Naked eye | |||||||||
T line | 357 | 351 | 49.6 (45.8–53.3) | 227 | 60 | 79.1 (73.9–83.7) | 128.7 | 38.9 (34.9–43.0) |
85.4 (81.6–88.7) |
NT line | 278 | 430 | 60.7 (57.0–64.4) | 241 | 46 | 84.0 (79.2–88.0) | 144.7 | 46.4 (42.1–50.8) |
90.3 (87.3–92.8) |
T and NT line |
222 |
486 |
68.6
(65.1–72.1) |
214 |
73 |
74.6
(69.1–79.5) |
143.2 |
49.1 (44.3–53.9) |
86.9 (83.9–89.6) |
Reader | |||||||||
T >1 and NT reader >28† | 130 | 451 | 77.6 (74.0–81.0) | 187 | 60 | 75.7 (69.9–80.9) | 153.3 | 59.0 (53.4–64.5) |
88.3 (85.2–90.9) |
*DPP (Dual Path Platform) Syphilis Screen & Confirm kit, Chembio (https://chembio.com). NPV, negative predictive value; NT line, antibodies against non–Treponema pallidum antigen; PPV, positive predictive value; T line, antibodies against T. pallidum antigen. †Values used as cutoff with the DPP reader were calculated to maximize the sum of sensitivity and specificity (Figure).