Table 3.
Comparison between saliva/ gargle and swabs for COVID-19 detection using RT-qPCR
| Type of samples | Country | No. of Samples | Sensitivity | Specificity | Overall agreement | NPV | PPV | Ct values | Main Findings | Ref. |
|---|---|---|---|---|---|---|---|---|---|---|
| NPS and saliva | Japan | 196 | - | - | NPS and saliva: 96.4% Kappa coefficient: 0.883 |
The same accuracy of saliva and NPS collected in an acute phase for detection of SARS-CoV-2 using RT-qPCR Saliva sample storage at room temperature did not affect the test results |
(24) | |||
| NPS/OPS,saliva and OR | USA | 570 | Saliva compared with NPSs: 94.1% |
Saliva compared with NPSs: 98.6% |
NPS and saliva: 97.7% Kappa coefficient: 0.93 |
- | - | Mean Ct (N2) in NPS and OPS: 22.6 and 28.6 |
Saliva is an acceptable alternative to NPSs for SARS-CoV-2 RNA detection by RT-qPCR No changes in viral loads of saliva over 24 hours storage at both RT and 4 ˚C |
(22) |
| Saliva compared with OPSs: 96.67% |
Saliva compared with OPSs: 91.43% |
OPS and saliva: 93% Kappa coefficient: 0.84 |
Mean Ct (N2) in saliva: 27.9 |
|||||||
| OR compared with NPS: 63.6 |
ORcompared with NPS: 96.9% |
ORand NPS: 85.7% Kappa coefficient: 0.65 |
Mean Ct (N2) in OR: 29.9 |
|||||||
| NPS and saliva | United Arab Emirates | 401 | Saliva compared to NPS: 73.1 % |
Saliva compared to NPS: 97.6% |
NPS and saliva: 96.0% Kappa coefficient: 0.68 |
98.1% | 67.9% | Good diagnostic accuracy and feasibility of utilization of specimen without transport media for Saliva | (29) | |
| NPS/OPS and saliva | Brazil | 155 | Saliva compared to NPS/OPS: 94.4% | Saliva compared to NPS/OPS: 97.62% |
NPS/OPS and saliva: 96.1% |
95.35% | 97.1% | High overall agreement between NPS/OPS and saliva | (28) | |
| NPS/OPS and saliva | Thailand | 150 | Compared to NPS/throat swabs: 84.2% |
Compared to NPS/throat swabs: 98.9% |
NPS/OPS and saliva: 97.5% Kappa coefficient: 0.851 |
98.4% | 88.9% | Median Ct (ORF1ab and N) in salvia: 32.7 and 31.8 |
High sensitivity and comparable performance of saliva to NPS/throat swab Strong agreement between NPS/throat swab and saliva sample |
(27) |
| Median Ct (ORF1ab and N) in NPS/throat swabs: 32 and 30.5 | ||||||||||
| NPS/OPS and saliva | Singapore | 42 | - | - | NPS and saliva: 69.0% | 52.4% | 95.2% | Ct in saliva: 25.77 ± 5.60 | Moderate agreement between self-collected saliva/buccal swabs and HCW-collected NPS | (33) |
| Ct in NPS: 22.95 ± 6.03 | ||||||||||
| NPS, saliva and gargle | Canada | 50 | Saline mouth rinse/gargle: 98% | - | - | Demonstrating higher combined user acceptability ratings and analytical performance for saline mouth rinse/gargle samples than saliva and HCW-collected NPS | (23) | |||
| Saliva sample: 79% | ||||||||||
| NPS and DTS | China | 95 | - | - | NPS and DTS: 78.9% Kappa coefficient: 0.58 |
Equivalent overall performance of DTS to that of the NPS | (30) |
DTS: deep throat saliva; HCW: healthcare workers; NPS: nasopharyngeal swabs; NPV: negative predictive value; OPS: oropharyngeal swabs; OR: Oral rinse; PPV: positive predictive value; RT: room temperature; RT-qPCR: quantitative reverse transcription polymerase chain reaction; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2.