Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.
Volume 31, Number 6—June 2025
Research
Diagnostic Accuracy of 3 Mpox Lateral Flow Assays for Antigen Detection, Democratic Republic of the Congo and United Kingdom
Table 2
Clinical diagnostic accuracy parameters of 3 MPXV antigen-detecting rapid diagnostic tests from 68 suspected mpox case-patients, the Democratic Republic of the Congo*
Category | Skin lesion swab samples, n = 68 |
Upper respiratory tract swab samples, n = 68 |
|||||
---|---|---|---|---|---|---|---|
Ecotest | Flowflex | Standard Q | Ecotest | Flowflex | Standard Q | ||
True positive | 3 | 3 | 2 | 0 | 0 | 0 | |
True negative |
49 |
49 |
49 |
54 |
54 |
54 |
|
False positive | 0 | 0 | 0 | 0 | 0 | 0 | |
False negative |
16 |
16 |
17 |
14 |
14 |
14 |
|
Specificity, % (95% CI) | 100 (92.7–100) | 100 (92.7–100) | 100 (92.7–100) | 100 (93.4–100) | 100 (93.4–100) | 100 (93.4–100) | |
Sensitivity, % (95% CI) |
15.79 (5.5–37.6) |
15.79 (5.5–37.6) |
10.53 (2.9–31.4) |
0 (0.0–23.2) |
0 (0.0–23.2) |
0 (0.0–23.2) |
|
PPV, % (95% CI) | 100 (29.2–100) | 100 (29.2–100) | 100 (15.8–100) | NA | NA | NA | |
NPV, % (95% CI) |
75.38 (71.6–78.8) |
75.38 (71.6–78.8) |
74.24 (71.2–77.1) |
79.41 (68.4–87.3) |
79.41 (68.4–87.3) |
79.41 (68.4–87.3) |
|
Sensitivity by Ct, % (95% CI) | |||||||
Ct <20 | 0 (0.0–79.4), n = 1 | 100 (20.7–100), n = 1 | 0 (0.0–79.4), n = 1 | NA | NA | NA | |
Ct <25 | 14.29 (2.6–51.3), n = 7 | 28.57 (8.2–64.1), n = 7 | 14.29 (2.6–51.3), n = 7 | 0 (0.0–79.4), n = 1 | 0 (0.0–79.4), n = 1 | 0 (0.0–79.4), n = 1 | |
Ct <33 | 27.27 (9.8–56.7), n = 11 | 27.27 (9.8–56.7), n = 11 | 18.18 (5.1–47.7), n = 11 | 0 (0.0–39.0), n = 6 | 0 (0.0–39.0), n = 6 | 0 (0.0–39.0), n = 6 | |
Ct <40 | 15.79 (5.5–37.6), n = 19 | 15.79 (5.5–37.6), n = 19 | 10.53 (2.9–31.4), n = 19 | 0 (0.0–21.5), n = 14 | 0 (0.0–21.5), n = 14 | 0 (0.0–21.5), n = 14 |
*Tests evaluated: Ecotest, Ecotest Monkeypox Antigen Rapid Test (Assure Tech [Hangzhou] Co., Ltd., https://www.assuretech-product.com); Flowflex, FlowFlex Monkeypox Virus Antigen Rapid Test (ACON Biotech [Hangzhou] Co., Ltd., https://www.aconbio.com); Standard Q, Standard Q Monkeypox Ag Test (SD Biosensor, https://www.sdbiosensor.com). Ct, cycle threshold; MPXV, monkeypox virus; NA, not available; NPV, negative predictive value; PPV, positive predictive value.
1These authors contributed equally to this article.
2Members of ISARIC 4C investigator group are listed at the end of this article.