Table 2.
Q-Plex™ Human Malaria assay diagnostic performance characteristics.
| Analyte | PCR-Confirmed species | n | Threshold (pg/mL) | Sensitivity (95%CI) | Specificity (95%CI) | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| vs controls | vs Pf | vs Pv | vs Pk | vs Pm | vs Po | vs all malaria | vs all malaria + controls | |||||
| Plasma | ||||||||||||
| HRP2 | Pf | 66 | 40.84 | 92.4 (83.2–97.5) | 98.0 (93.1–99.8) | - | 97.4 (90.9–99.7) | 91.3 (84.9–95.6) | 100 (86.8–100) | 100 (66.4–100) | 94.6 (90.9–97.1) | 95.6 (92.9–97.5) |
| Pf-LDH | Pf | 66 | 17.81 | 89.4 (79.4–95.6) | 97.1 (91.6–99.4) | - | 61.0 (49.3–72.0) | 69.8 (61.0–77.7) | 3.9 (0.1–19.6) | 10 (0.3–44.5) | 57.3 (50.8–63.7) | 69.2 (64.0–74.1) |
| Pf-LDH | Pm | 26 | 17.81 | 96.2 (80.4–99.9) | As above | 10.6 (4.4–20.6) | As above | As above | - | As above | 51.3 (45.2–57.3) | 63.5 (58.5–68.4) |
| Pf-LDH | Pk | 126 | 17.81 | 30.2 (22.3–39.0) | As above | As above | As above | - | 3.9 (0.1–19.6) | As above | 31.3 (24.6–38.6) | 55.2 (49.1–61.1) |
| Pv-LDH | Pv | 77 | 9.14 | 80.5 (69.9–88.7) | 99.0 (94.7–100) | 83.3 (72.1–91.4) | - | 3.2 (0.9–7.9) | 88.5 (69.9–97.6) | 80 (44.4–97.5) | 39.5 (33.1–46.1) | 57.9 (52.4–63.3) |
| Pv-LDH | Pk | 126 | 9.14 | 96.8 (92.1–99.1) | As above | As above | 19.5 (11.3–30.1) | - | As above | As above | 56.4 (48.8–63.8 | 71.9 (66.2–77.1) |
| Pan-LDH | All malaria | 305 | 27.56 | 90.2 (86.3–93.3) | 99.0 (94.7–100) | - | - | - | - | - | - | - |
| CRP | All malaria | 305 | 26,212a | 86.6 (82.2–90.2) | 97.1 (91.6–99.4) | - | - | - | - | - | - | - |
| Whole blood | ||||||||||||
| HRP2 | Pf | 63 | 4.31 | 100 (94.3–100) | 98.0 (93.1–99.9) | - | 92.4 (83.2–97.5) | 93.9 (85.2–98.3) | 95.8 (78.9–99.9) | - | 93.0 (87.9–96.5) | 95.0 (91.6–97.3) |
| Pf-LDH | Pf | 63 | 12.64 | 100 (94.3–100) | 96.1 (90.3–98.9) | - | 10.6 (4.4–20.6) | 47.0 (34.6–59.7) | 0 (0–14.3) | - | 24.1 (17.6–31.5) | 52.3 (46.1–58.5) |
| Pf-LDH | Pm | 24 | 12.64 | 100 (85.8–100) | As above | 0 (0–5.7) | As above | As above | - | - | 19.3 (14.0–25.5) | 45.5 (39.7–51.3) |
| Pf-LDH | Pk | 66 | 12.64 | 53.0 (40.3–65.4) | As above | As above | As above | - | 0 (0–14.3) | - | 4.5 (1.8–9.1) | 40.9 (34.8–47.1) |
| Pv-LDH | Pv | 66 | 75.66 | 93.9 (85.2–98.3) | 99.0 (94.7–100) | 93.7 (84.5–98.2) | - | 6.1 (1.7–14.8) | 100 (85.8–100) | - | 57.4 (49.2–65.3) | 73.9 (68.1–79.2) |
| Pv-LDH | Pk | 66 | 75.66 | 93.9 (85.2–98.3) | As above | As above | 6.1 (1.7–14.8) | - | as above | - | 57.4 (49.2–65.3) | 73.9 (68.1–79.2) |
| Pan-LDH | all malaria | 221 | 84.42 | 95.5 (91.8–97.8) | 99.0 (94.7–100) | - | - | - | - | - | - | - |
| CRP | all malaria | 221 | 13,768a | 80.1 (74.2–85.2) | 99.0 (94.7–100) | - | - | - | - | - | - | - |
PCR polymerase chain reaction, n number of samples, CI confidence interval, Pf Plasmodium falciparum, Pv Plasmodium vivax, Pk Plasmodium knowlesi, Pm Plasmodium malariae, Po Plasmodium ovale, HRP2 Histidine-rich protein-2, LDH lactate dehydrogenase, CRP C-reactive protein.
aUnits of ng/mL.