Table 1

Detection methods for coronaviruses

CoronavirusMethodSampleTiming (days after onset)ReferencesConjunctivitis
SARS-CoVELISATear (conjunctival swabs)7–10 days13Not reported, but RT-PCR and ELISA detection of patient’s tears were positive.
Blood serum
PCRTear (conjunctival swabs)12 days21
RT-PCRBlood serumIn the second week22
Respiratory secretions
Lung tissue
SARS-CoV-2RT-PCRBALFReported, RT-PCR conjunctival swab results were positive in a small range of patients.
Deep sputum17
Conjunctival swabs23
RT-PCRUpper respiratory secretions (nasopharyngeal and oropharyngeal swabs)4 days24
Serum11 days
Stool7 days
ELISABlood serumAcute phase, remission phase13
Gene sequencingBlood serum12
HCoV-NL63RT-PCRRespiratory samples (nasal aspirates and swabs)25Reported; no detection of eye tissue was reported
Gene sequencingNasopharyngeal aspirate specimen5 days14
MERS-CoVRT-PCRRespiratory tract samples, such as nasopharyngeal swab, sputum, deep tracheal aspirate, etc26Not 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.