Table 4.

Comparison of current SARS-CoV-2 current diagnosis approaches reviewed.

Type of Assay		Target type		Time needed	Site where testing takes place	Advantage		Limitation		Suggested use
		Looks for	Targeting at
Direct testing	rRT-PCR	Virus replication (active infection)	Virus genome	3–4 h	Laboratory	Highly sensitive and specific		High turnaround condition*, requires skilfull personnel and its expensive		COVID-19 diagnosis and screening of contacts among infectious cases
	Ag-based RDT		Viral antigens	15 min	POC diagnosis	Easy-to-use, low turnaround condition, cheaper		Low sensitivity and specificity. Needs further diagnosis confirmation.		A Large-scale screening diagnostic test
Indirect testing ELISAs		Host antibody response (active and past infection)	Antibodiesa	1–3 h	Laboratory	Sample collection supposes a lower exposure risk	Highly sensitive and specific	Time-dependent on the host antibody development	High turnaround condition, requires skilfull personnel and its expensive	Identifying possible human donors for collection of convalescent serum, during vaccine trials and recognizing possible animal hosts for SARS-CoV-2	A complement to RNA testing, especially since the 2nd week after symptoms onset. Immunoglobulins detection reveal information about the time course of the infection.
	CLIAs		Antibodiesb	1–3 h	Laboratory
	Ab-based RDT		Antibodiesc	15 min	POC diagnosis		Easy-to-use, low turnaround condition, cheaper		Low sensitivity and specificity		Screening seroprevalence levels among the population

^aEither IgM or IgG, or both, or IgA, or total antibodies.

^bEither IgM or IgG, or both, or total antibodies.

^cEither IgM or IgG, or both.

^*The turn-around time of rapid tests lasts about an hour.