Table 4.

Summary of the papers that examined cirrhotic, non-cirrhotic and various pre-cirrhotic stage occasion patients against each other. The arrows show (if applicable) whether a VOC level increased or decreased in the first group compared to the second group in the study design.

Author/Year	Study Design	Analytical Method	VOCs Identified as Significant	Discriminatory Performance
Alkhouri et al. 2015	20 advanced fibrosis vs. 41 mild fibrosis	SIFT-MS	Acetone ↓ Benzene ↓ Carbon disulphide ↓ Isoprene ↓ Pentane ↓ Ethane ↓	0.85 AUC (Isoprene model)
Khalid et al. 2013	11 alcoholic cirrhotic with HE vs. 23 alcoholic cirrhotic without HE	GC-MS	Methyl-vinyl ketone ↓ Isothiocyanato-cyclohexane ↑	90% sensitivity 87% specificity
	34 alcoholic cirrhotic vs. 13 non-alcoholic cirrhotic		Undecane ↑ Unknown ↓	78.3% sensitivity 69.2% specificity
	34 alcoholic cirrhotic vs. 7 harmful drinkers		1-methyl-4-(1-methyl-ethenyl)-benzene ↑ Unknown ↓ Unknown ↓	88% sensitivity 85% specificity
	7 harmful drinkers vs. 15 healthy		Octanal 2,6-dimethyl-7-octen-2-ol Unknown	71% sensitivity 93% specificity
	13 non-alcoholic cirrhotic vs. 15 healthy		Methyl-vinyl ketone 1-methyl-2-(1-methyl-ethyl)-benzene (o-cymene) Unknown	92% sensitivity 100% specificity
	34 alcoholic cirrhotic vs. 15 healthy		Heptane 1-methyl-2-(1-methyl-ethyl)-benzene Phellandrene 2-methyl-hexane	97% sensitivity 93% specificity
O’Hara et al. 2016	11 cirrhotic HE vs. 11 cirrhotic without HE vs. 7 history of HE vs. 30 healthy	PTR-MS	Limonene ↑	Not reported
	10 without HCC vs. 21 HCC vs. 30 healthy		Limonene ↑	Not reported
Qin et al. 2010	30 HCC vs. 36 healthy	GC-MS-SPME	3-hydroxy-2-butanone ↑ Styrene ↑ Decane ↑	83.3% sensitivity 91.7% specificity
	30 HCC vs. 27 cirrhotic without HCC		3-hydroxy-2-butanone ↑ Styrene ↑	70% sensitivity 70.4% specificity
Ferrandino et al. 2020	32 cirrhotic without HCC vs. 12 cirrhotic with HCC vs. 40 healthy controls	GC-MS	Limonene ↑	73% sensitivity 77% specificity
Miller-Atkins et al. 2020 † only the three most significant metabolite associations for each disease comparison are shown in the column of significant compounds	112 non-cirrhotic HCC vs. 54 healthy	SIFT-MS	(E)-2-nonene ↑ Ethane ↑ Benzene ↑ Hydrogen sulphide ↓	Healthy vs. all the rest 76% sensitivity 97% specificity
	30 cirrhotic without HCC vs. 54 healthy		Trimethyl-amine ↓ Propanol ↓	Cirrhotic vs. all the rest 40% sensitivity 96% specificity
	49 PH vs. 54 healthy		(E)-2-nonene ↑ Acetaldehyde ↑ Ethane ↑ Hydrogen sulphide ↓	HCC vs. all the rest 73% sensitivity 71% specificity
	51 CRLM vs. 54 healthy		(E)-2-nonene ↑ Acetaldehyde ↑ Triethyl-amine ↑ Acetone ↓	CRLM vs. all the rest 51% sensitivity 94% specificity
	112 non-cirrhotic HCC vs. 30 cirrhotic		Acetone ↓ Acetaldehyde ↓ Dimethyl-sulphide ↓ Ethanol ↑	PH vs. all the rest 58% sensitivity 93% specificity
Arasaradnam et al. 2016	22 non-cirrhotic HE vs. 20 healthy	E-nose	Not available	88% sensitivity 68% specificity
	13 covert non-cirrhotic HE vs. 9 overt non-cirrhotic HE		Not available	79% sensitivity 50% specificity
Solga et al. 2008	16 moderate to severe steatosis vs. 11 less steatosis	GC	Ethanol ↑ Acetone ↑	Not reported
	24 NASH vs. 24 without NASH		Acetone ↑	Not reported
Verdam et al. 2013	39 NASH vs. 26 without NASH	GC-MS	n-tridecane ↑ 3-methyl-butanonitrile ↑ 1-propanol ↑	90% sensitivity 69% specificity
Alkhouri et al. 2013	37 obese NAFLD vs. 23 obese without NAFLD	SIFT-MS	Isoprene ↑ Acetone ↑ Trimethylamine ↑ Acetaldehyde ↑ Pentane ↑	0.76 AUC
Millonig et al. 2010	37 cirrhotic vs. 35 healthy	IMR-MS	Ethanol ↑	0.88 AUC
	91 liver diseased vs. healthy		Acetaldehyde ↑ Ethanol ↑ Isoprene ↑	0.94 AUC
	34 NAFLD vs. healthy controls		Acetaldehyde ↑	0.96 AUC
	20 AFLD vs. 35 healthy		Acetaldehyde ↑ Isoprene ↑	0.97 AUC
	20 AFLD vs. 34 NAFLD		Isoprene ↑	0.95 AUC
Letteron et al. 1993	89 alcohol abusers vs. 52 liver diseased vs. 42 healthy	GC-FID	Ethane ↑	Not reported
Hanouneh et al. 2014	80 liver diseased vs. 43 healthy	SIFT-MS	2-propanol ↑ Acetaldehyde ↑ Acetone ↑ Ethanol ↑ Pentane ↑ Trimethylamine ↑	Not reported
	40 cirrhotic AH vs. 40 cirrhotic AD		Acetaldehyde ↑ Acetone ↑ Pentane ↑ Trimethylamine ↑	97% sensitivity 72% specificity (Acetone-pentane-trimethylamine)