TABLE 3.

Antigen-based lateral flow assay of SARS-CoV-2.

Target	Detection technique	Signal readout	LOD	Sensitivity, specificity	Time	Reference
S protein	nanozyme and enzymatic chemiluminescence immunoassay with the lateral flow strip	fluorescence	0.1 ng/ml	—	15 min	Liu et al. (2020a)
N protein	fluorescence immunochromatographic lateral flow assay	fluorescence	—	98%, 100%	10 min	Diao et al. (2020)
N protein	fluorescence immunochromatographic lateral flow assay	fluorescence	—	85%, 100%	<15 min	Escrivá et al. (2021)
S & N protein	up-conversion nanoparticles labeled lateral flow immunoassay	fluorescence	1.6 ng/ml, 2.2 ng/ml	—	10 min	Guo et al. (2021)
N protein	half-strip lateral flow assay	fluorescence	0.65 ng/ml	—	20 min	Grant et al. (2020)
N protein	open-access lateral flow assay	colorimetric	2.5 × 104 copies/swab	69, 97; 83, 97%	—	Grant et al. (2021)
recombinant antigen	microfluidic immunoassay system	fluorescence	—	—	<15 min	Lin et al. (2020)
spike RBD protein	LFA based on gold nanospheres	thermal contrast amplification reading	0.016 fg/ml (in buffer), 0.125 fg/ml (in nasopharyngeal wash)	—	30 min	Liu et al. (2021c)
N protein	phage display technology integrated with LFIA-based biosensor	colorimetric	2 ng	—	20 min	Kim et al. (2021)
antigen cocktail	colorimetric lateral flow immunoassay	colorimetric	—	93%	5–10 min	Ghorbanizamani et al. (2021)