Table 4.
Compilation of strategies of isothermal amplification explored for SARS-CoV-2 diagnostic.
| Method | Variations | Region targeted | Single or multiple targeting | Temperature of reaction (°C) | Duration of amplification (min) | Included in assay issued with EUA | Source | |
|---|---|---|---|---|---|---|---|---|
| Isothermal amplification | LAMP | RT-LAMP | ORF1ab, S, N,M, ORF3a,ORF7a | Single, or Multiple | 60-65 | 40-60 | Yes* | (Schermer et al., 2020; Lalli et al., 2021) |
| Mismatch-tolerant RT-LAMP | ORF1ab, S, N | Single | 63 | 50 | No* | (Lu et al., 2020a) | ||
| Barcoded RT-LAMP | N | Single | 65 | 60 | No* | (Schmid-Burgk et al., 2020) | ||
| TMA | _ | ORF1ab | Multiple | _ | _ | Yes* | (Pham et al., 2020) | |
| NASBA | _ | S and N | Single, or Multiple | 41 | 35-130 | No* | (Xing et al., 2020; Wu et al., 2021) | |
| RPA | RT-RPA | ORF1ab, S, N, E | Single, or Multiple | 42 | 15-30 | No* | (Qian et al., 2020; Xia and Chen, 2020; El Wahed et al., 2021; Sun et al., 2021) | |
| RCA | _ | ORF1ab | Single | 23 | 5-15 | Yes* | (Kim et al., 2021) | |
| C2CA | HC2CA | RdRp | Single | 37 | 90 | No* | (Tian et al., 2020) | |
| HDA | RT-HDA | _ | _ | _ | _ | Yes* | (Quidel, 2020) | |
| EXPAR | RTF-EXPAR | ORF1ab | Single | 50 | <5-25 | No* | (Carter et al., 2021) | |
| SDA | AMC-SDA | N | Single | 55 | 30 | No* | (Zhang et al., 2021b) | |
| MCDA | RT-MCDA | ORF1ab, N | Single or Multiple | 65 | 35-60 | No* | (Li et al., 2020; Luu et al., 2021) | |
| LAMP/RPA | Penn-RAMP | ORF1ab | Single | 38 (RPA) and 63 (LAMP) | 40 | No* | (Song et al., 2021) |
*Retrieved from the instructions for use of approved diagnostic products available in FDA website (https://www.fda.gov/medical-devices/coronavirus-disease-2019-covid-19-emergency-use-authorizations-medical-.devices/in-vitro-diagnostics-euas-molecular-diagnostic-tests-sars-cov-2).