Table 1

Detection methods for coronaviruses

Coronavirus	Method	Sample	Timing (days after onset)	References	Conjunctivitis
SARS-CoV	ELISA	Tear (conjunctival swabs)	7–10 days	¹³	Not reported, but RT-PCR and ELISA detection of patient’s tears were positive.
		Blood serum
	PCR	Tear (conjunctival swabs)	12 days	²¹
	RT-PCR	Blood serum	In the second week	²²
		Respiratory secretions
		Urine
		Stool
		Lung tissue
SARS-CoV-2	RT-PCR	BALF			Reported, RT-PCR conjunctival swab results were positive in a small range of patients.
		Deep sputum		¹⁷
		Conjunctival swabs		²³
	RT-PCR	Upper respiratory secretions (nasopharyngeal and oropharyngeal swabs)	4 days	²⁴
		Serum	11 days
		Stool	7 days
	ELISA	Blood serum	Acute phase, remission phase	¹³
	Gene sequencing	Blood serum		¹²
HCoV-NL63	RT-PCR	Respiratory samples (nasal aspirates and swabs)		²⁵	Reported; no detection of eye tissue was reported
	Gene sequencing	Nasopharyngeal aspirate specimen	5 days	¹⁴
MERS-CoV	RT-PCR	Respiratory tract samples, such as nasopharyngeal swab, sputum, deep tracheal aspirate, etc		²⁶	Not reported

BALF, bronchoalveolar lavage fluid; HCoV-NL63, human coronavirus NL63; MERS-CoV, Middle East respiratory syndrome coronavirus; RT-PCR, reverse-transcription PCR; SARS-CoV2, severe acute respiratory syndrome coronavirus 2.