Breath biomarkers in idiopathic pulmonary fibrosis: a systematic review

Respiratory Research

Table 2 Biomarkers reported to discriminate between IPF patients and healthy controls. Direction of discrimination and reported p-value. ^aC_alvNO. ^bFeNO₅₀/FeNO₁₀₀/FeNO₁₅₀/C_alvNO

Biomarker	Sample Medium	Discrimination	p-value	References
Nitric Oxide	Exhaled breath	Higher in IPF	0.0001, < 0.0001	[62]^a, [65]^b
8-isoprostane	EBC	Higher in IPF	0.02, < 0.05	[58], [62]
Hydrogen Peroxide	EBC	Higher in IPF	0.003	[58]
Nickel	EBC	Higher in IPF	< 0.05	[59]
Chromium	EBC	Higher in IPF	< 0.05
Silicon	EBC	Higher in IPF	< 0.05
Cobalt	EBC	Lower in IPF	< 0.05
Iron	EBC	Lower in IPF	< 0.05
Copper	EBC	Lower in IPF	< 0.05
Selenium	EBC	Lower in IPF	< 0.05
Molybdenum	EBC	Lower in IPF	< 0.05
Nitrite	EBC	Higher in IPF	< 0.01	[60]
Nitrate	EBC	Lower in IPF	< 0.01	[60]
22:4 LPA	EBC	Higher in IPF	0.001	[63]
Unidentifiable metabolite	EBC	Higher in IPF	≤0.01	[64]
p-cymene	Exhaled breath	Lower in IPF	< 0.001	[66]
Acetoin	Exhaled breath	Higher in IPF	< 0.001
Isoprene	Exhaled breath	Higher in IPF	< 0.001
Ethylbenzene	Exhaled breath	Higher in IPF	< 0.001
Unidentified VOC	Exhaled breath	Higher in IPF	< 0.001

IPF idiopathic pulmonary fibrosis, EBC exhaled breath condensate, 22:4 LPA Docosatetraenoyl lypophosphatidic acid, VOC volatile organic compound, C_alvNO alveolar nitric oxide concentration, FeNO_50/100/150 fractionated exhaled nitric oxide at 50 ml/100 ml/150 ml per second

ISSN: 1465-993X