Table 4. List of 74 metabolites identified in human serum polar and lipid extracts.

Amino acids	Organic acids	Lipids	Misc
Glycine	2-aminobutyric acid	Arachidonic acid	D-Fructose
L-Alanine	Alpha-Hydroxyisobutyric acid	Cholesterol	D-Galactopyranose
L-Asparagine	2-Methylbutanoic acid	Capric acid	D-Galactose
L-Aspartic acid	3-Hydroxybutyric acid	Dodecanoic acid	Glucitol
L-Cysteine	4-Hydroxybutyric acid	Arachidic acid	D-Glucose
L-Cystine	Aminomalonic acid	Heptadecanoic acid	Glycerol
L-Glutamic acid	Benzoic acid	Linoleic acid	D-Glucopyranose
L-Glutamine	Citric acid	Oleic acid	Hydroxyproline
L-Histidine	Erythronic acid	Palmitelaidic acid	D-Maltose
L-Isoleucine	Fumaric acid	Palmitic acid	Myo-inositol
L-Leucine	Gluconic acid	Stearic acid	Acetylglycine
L-Lysine	Glyceric acid	Myristic acid	N-Acetyl-L-Lysine
L-Methionine	Isobutyric acid		Acetaminophen
L-Ornithine	Tartaric acid		Phosphoric acid
L-Phenylalanine	L-Lactic acid		Ribitol
L-Proline	Malonic acid		Salicylic acid
L-Serine	Methylmaleic acid		Urea
L-Threonine	Methylmalonic acid		D-Xylitol
L-Tryptophan	Nicotinic acid
L-Tyrosine	Oxalic acid
L-Valine	Pyroglutamic acid
	Succinic acid
	Uric acid