Table 5. Evaluation of the intrinsic parameters of the combo RT-qPCR assay for the diagnosis of human rabies, using the RT-hnPCR as the referent method.
| Type of sample | Total numbera | Combo RT-qPCR result | Mean Cq value ± SD | Sensitivity | Specificity | Positive predicted value | Negative predicted value | ||
|---|---|---|---|---|---|---|---|---|---|
| No. pos. samples/Total no. of samples (%) | |||||||||
| From all patients | From pos. patients | ||||||||
| Sample | Skin biopsy | 67 | 43/67 (64.2) | 43/47 (91.5) | 31.53 ± 4.38 | 102b | 100 | 100 | 96.3 |
| Saliva | 120 | 20/120 (16.7) | 20/37 (54) | 33. 93 ± 3.00 | 74c | 100 | 100 | 93.4 | |
| CSF | 12 | 3/12 (25) | 3/7 (42.9) | 25.3 ± 0.14 | 100 | 100 | 100 | 100 | |
| Brain biopsy | 12 | 10/12 (83.3) | 10/10 (100) | 21.4 ± 5.56 | 100 | 100 | 100 | 100 | |
| Total | 211 | 76/211 (36) | 76/101 (75.2) | 30.70 ± 5.7 | 92.7 | 100 | 100 | 95.6 | |
| Patientd | 65 | 41/65 (63.1) | 41/41 (100) | 41/65 (61.5) | 100 | 100 | 100 | 100 | |
a Total number includes samples tested in Cambodia, France and Morocco from all patients (negative and positive for rabies).
b One additional skin biopsy sample was detected with the pan-RABV RT-qPCR (n = 43) compared to the RT-hnPCR (n = 42).
c 8 saliva samples from a same patient were not detected and one saliva sample from another patient was detected with the pan-RABV RT-qPCR compared to the RT-hnPCR, leading to a total of n = 20 and n = 27 saliva samples detected for the pan-RABV RT-qPCR and the RT-hnPCR, respectively.
d Including all patients, with rabies-confirmed and negative patients.