Table 1.
A comparison of the proposed label-free CLIA with other reported methods for SARS-CoV-2 NP detection.
| Analytical Method for SARS-CoV-2 NP | Labeled or Label-free | Linear Range | LOD | Manual Operation | Test Time |
|---|---|---|---|---|---|
| LFA[16] | Labeled | Semiquantitative | 2 ng | + | 20 min |
| Half-Strip LFA[17] | Labeled | Semiquantitative | 0.65 ng mL−1 | + | 20 min |
| Immunochromatography[18] | Labeled | Semiquantitative | 100 ng mL−1 | + | >15 min |
| Aptamer-assisted Proximity Ligation Assay[20] | Labeled | 50–5000 pg/mL | 37.5 pg/mL | + | 2 h |
| Mass Spectrometry[19] | Label-free | 3 aM to 12.5 fM※ | 200 aM | + | >4 h |
| Electrochemical Immunosensor[35] | Label-free | 1 pg/mL to 1000 ng mL−1 | 0.8 pg/mL | + | >20 min |
| This work | Label-free | 0.1 pg/mL to 10,000 pg/mL | 21 fg mL−1 | – | 25 min |
“+”: need manual operation; “−”: automatic method without manual operation.
“*”: the limit of quantitation was 390 aM.