Table 2.

Main results of volatile organic compound breath analysis in patients with interstitial lung disease using chromatography and spectroscopy

Author	Year	Patient groups (n=)	Technique	Comparison	Discriminative compounds (n=)	Performance (AUC/accuracy)
Plantier et al.[19▪▪]	2022	IPF (53) CTD-ILD (51) HC (51)	GC-tof-MS	IPF vs. HC CTD-ILD vs. HC IPF vs. CTD-ILD	34 11 16	0.91/84.6% 0.84/77.5% 0.84/76.9%
Yamada et al.[20]	2017	IPF (40) HC (55)	MCC-IMS	IPF vs. HC	5	-/76.8–83.2%a
Yang et al.[17]	2017	Pneumoconiosis (25) Stone workers (154)	GC-MS	Pneumoconiosis vs. exposed	9	0.90/– c
Fijten et al.[16]	2017	Sarcoidosis (87)b HC (26)	GC-tof-MS	Sarcoidosis vs. HC	9	0.76/74.1%c
Jalali et al.[18]	2016	Silicosis (4) HC (45)d Silica exposed (20)	GC-MS	Silicosis vs. exposed Silicosis vs. HC	Multiple results	Not reported
Westhoff et al.[15]	2007	Sarcoidosis (5)e Sarcoidosis suspected (4)f	MCC-IMS	Sarcoidosis vs. suspected	13	No statistical test results reported
Hayton et al.[21]	2020	IPF (46)	GC-MS	Stable vs. disease progression at 6 months	1	N/A
Guiot et al.[22]	2020	SSc (27, of which 17 with SSc-ILD)	Unknown	SSc-ILD vs. SSc without ILD	0	N/A

Main results of the cited articles are displayed. Conference abstracts are shown in italic.

^aA separate accuracy for each of the discriminative VOCs was calculated. AUC, area-under-the-curve; CTD, connective tissue disease; GC, gas chromatography; HC, healthy control; ILD, interstitial lung disease; IMS, ion mobility spectrometry; IPF, idiopathic pulmonary fibrosis; MCC, multicapillary column (i.e. variation of a capillary gas chromatograph); MS, mass spectrometry; SSc, systemic sclerosis; tof, time of flight (i.e. type of mass analyzer).

^bn = 18 had Scadding stage 0.

^cResults of test/validation cohorts or cross-validation analyses are displayed here.

^dGroup was split in 20 nonsmoking and 25 smoking individuals.

^eNot all patients had ILD.

^fSarcoidosis excluded after biopsy of mediastinal lymphadenopathy.