TABLE 1.

Basic characteristics of the included literature.

References	Age (year)	Background disease	Time interval (day)	Study type	Country	Sample	TP	FP	FN	TN
Shujaat et al. (10)	54.3	No	/	Retrospective	America	87	49	7	16	15
Chan et al. (11)	61.5	No	16	Retrospective	America	101	46	10	7	38
Dornia et al. (12)	58	No	90	Retrospective	Britain	172	72	4	42	54
Rajaram et al. (13)	62	Connective tissue disease	2	Retrospective	America	77	30	6	25	16
Mahammedi et al. (14)	63.5	No	90	Retrospective	America	400	211	24	87	78
Iyer et al. (15)	56.25	COPD	120	Retrospective	America	60	16	6	6	32
Shin et al. (16)	59	COPD	90	Retrospective	America	65	19	2	19	25
Scelsi et al. (17)	64	No	120	Retrospective	America	186	72	11	55	48
Degani-Costa et al. (18)	58.22	No	180	Retrospective	Brazil	32	11	0	4	17
Condliffe et al. (19)	66	Systemic sclerosis	90	Retrospective	Britain	67	38	2	10	17
Mohamed Hoesein et al. (20)	70.1	No	60	Retrospective	America	620	199	37	176	208
Ratanawatkul et al. (21)	55.1	COPD	180	Retrospective	Netherland	92	15	9	15	53

TP, true positive; FP, false positive; TN, true negative; FN, false negative.