Table 2.

Comparation of different clinical and non-clinical specimens.

specimens	sites	viral loads or positive rates	process procedures	Ref.
throat/pharyngeal/oropharyngeal swab	upper respiratory tract	32% a 44.2% b	nasopharyngeal or throat swab specimens can induce coughing and sneezing, which generates aerosol and is a potential health hazard for health-care workers	NA
nasal swab		63% a
posterior oropharyngeal saliva (deep throat saliva)		highest during the first week after symptom onset then declined with time	brought up by a throat-clearing manoeuvre	To et al. (2020a) To et al. (2020b) To et al. (2019)
deep sputum induced sputum	lower respiratory tract	72% a 76.9% b	induced sputum (ie, 10 mL of 3% hypertonic saline was inhaled through a mask with oxygen at a flow rate of 6 L/min for 20 min or until the sputum was produced)	Han et al. (2020)
BALF (bronchoalveolar lavage fluid)		93% a	NA	NA
feces	NA	29% a
rectal swabs		NA		To et al. (2020a)
blood		1% a		NA
urine		0% a 73.6% c
fibrobronchoscope brush biopsy		46% a
aerosols	environmental contamination	NA	generated with the use of a three-jet Collison nebulizer and fed into a Goldberg drum to create an aerosolized environment	Ong et al. (2020)
other abiotic material surface (copper, cardboard, plastic and stainless steel etc.)			NA

^aMeans RT-qPCR positive rates from ref. (Wang et al., 2020b).

^bMeans RT-qPCR positive rates from ref. (Lin et al., 2020).

^cMeans detected nucleocapsid protein in urine in 73.6% of diagnosed COVID-19 patients (Diao et al., 2020). NA: not available.