Organic Acids Test (The Great Plains Laboratory)

2-Hydroxybutyric acid is a by-product of glutathione production. Levels of 2-Hydroxybutyric acid in the urine may reflect levels of glutathione production.

2-Hydroxyhippuric acid is a conjugate of hydroxybenzoic acid (salicylic acid) and glycine.

2-Hydroxyisocaproic acid (aka Leucic acid / α-hydroxyisocaproic acid / HICA) is a metabolite of the branched-chain amino acid leucine.

2-Hydroxyisovaleric acid (aka 2-Hydroxy-3-methylbutyric acid) is a branched-chain amino acid metabolite.

The metabolite of phenylalanine via phenyl pyruvate.

2-Oxo-4-methylthiobutanoic acid, also known as 4-(methylsulfanyl)-2-oxobutanoate or 2-keto-4-methylthiobutyrate, belongs to the class of organic compounds known as thia fatty acids. Thia substituted fatty acids are saturated fatty acids which are modified by insertion of a sulfur atom at specific positions in the carbon backbone.

2-Oxoglutaric acid is an organic acid that is important for the proper metabolism of all essential amino acids. It is formed in the Krebs cycle, the energy-producing process that occurs in most body cells.

2-Oxoisocaproic acid (also known as Ketoleucine) is an abnormal metabolite that arises from the incomplete breakdown of branched-chain amino acids.

2-Oxoisocaproic acid is both a neurotoxin and a metabotoxin.

2-Oxoisovaleric acid is an abnormal metabolite that arises from the incomplete breakdown of branched-chain amino acids (=BCAA). 2-Oxoisovaleric acid is a neurotoxin, an acidogen, and a metabotoxin. 

- A precursor in the production of cholesterol in both humans and yeast.

- Elevated levels may also indicate decreased CoQ10 synthesis.

- Moderate increases are probably due to yeast overgrowth of the GI tract and might also implicate yeast overgrowth with elevated serum cholesterol.

- Very elevated levels may be due to HMG aciduria (=3-hydroxy-3-metylglutaric aciduria)

3-Hydroxybutyric acid is a typical partial-degradation product of branched-chain amino acids (primarily valine) released from muscle for hepatic and renal gluconeogenesis. This acid is metabolized by 3-hydroxybutyrate dehydrogenase. The enzyme functions in nervous tissues and muscles, enabling the use of circulating hydroxybutyrate as a fuel.

3-Hydroxyglutaric is a marker for glutaryl CoA dehydrogenase deficiency.

3-Indoleacetic is a Tryptophan byproduct of Clostria: C. stricklandii, C. litusburense, C. subterminale, and C. putrefaciens.

3-Methyl-2-oxovaleric acid is an abnormal metabolite that arises from the incomplete breakdown of branched-chain amino acids. 

Moderate increase may result from lactic acidosis, episodic ketosis, or thiamine/lipoic acid deficiency. Significant elevations are associated with genetic issues, MSUD, and pyruvate dehydrogenase deficiency.

- Slight elevations may be due to deficiencies of the vitamins thiamine or lipoic acid.

- Elevated values are also associated with the genetic diseases maple syrup urine disease or pyruvate dehydrogenase deficiency.

The marker, 3-methylglutaconic acid in high values indicates a reduced ability to metabolize the amino acid, leucine. This abnormality is found in the genetic disease, methylglutaconic aciduria and in mitochondrial disorders.

3-methylglutaric acid is an organic acid classically associated with two distinct leucine pathway enzyme deficiencies.

3-Oxoglutaric indicates yeast overgrowth in the gastrointestinal tract. 

4-Cresol has been used as a specific marker for Clostridium difficile.

4-Hydroxybenzoic Acid is a marker for intestinal dysbiosis.

A moderate urinary increase in 4-hydroxybutyric acid may be due to intake of dietary supplements containing 4-hydroxybutyric acid, also known as gamma-hydroxybutyric acid. Very high levels may indicate the genetic disorder 3-methylglutaconic aciduria involving succinic semialdehyde dehydrogenase deficiency.

4-Hydroxyhippuric is a glycine conjugate of 4-hydroxybenzoic acid, the paraben metabolite.

A tyrosine metabolic product of GI bacteria.

4-hydroxyphenyllactate is present in relatively higher concentrations in the cerebrospinal fluid and urine of patients with phenylketonuria (PKU) and tyrosinemia.

5-Hydroxyindoleacetic acid (5HIAA) is a breakdown product of serotonin that is excreted in the urine. Serotonin is a hormone found at high levels in many body tissues. Serotonin and 5HIAA are produced in excess amounts by carcinoid tumors, and levels of these substances may be measured in the urine to test for carcinoid tumors.

A metabolite produced by Aspergillus and possibly other fungal species in the GI tract.

Acetoacetic acid (=acetoacetate) is a ketone body and a weak Beta-keto acid produced from acetyl-CoA in the mitochondrial matrix of hepatocytes.

Elevated in mitochrondrial disorders. Aconitase metabolizes citric and aconitic acids, and is dependent on glutathione.

Adipic Acid, together with Suberate and Ethylmalonate are all functional markers for deficiency of carnitine.

Breakdown product of hyaluronic acid; also found in certain foods.

Ascorbic Acid is a natural water-soluble vitamin (Vitamin C). Ascorbic acid is a potent reducing and antioxidant agent that functions in fighting bacterial infections, in detoxifying reactions, and in the formation of collagen in fibrous tissue, teeth, bones, connective tissue, skin, and capillaries.

Carboxycitric is a metabolite of yeast/fungi and general indicator of gastrointestinal dysbiosis. Elevated yeast/fungal metabolites indicate overgrowth in the GI tract.

Metabolite of yeast or anaerobic bacteria, including Clostridia.

Citric acid, cis-aconitic acid, and isocitric acid are the first three metabolites in the Krebs Citric Acid energy production cycle, which operates in the mitochondria of your cells. 

Produced when Clostridia acts upon unabsorbed tryptophan, tyrosine or phenylalanine.

HVA and DOPAC are the major metabolites of dopamine.

Ethylmalonate, together with Adipate and Suberate, gives information about your ability to process fatty acids.

Fumarate (together with Succinate and Malate) is used in the body’s metabolic pathway that generates cellular energy – the Citric Acid Cycle.

Furan 2,5-dicarboxylic is a byproduct of Aspergillus and other fungal species.

Furancarbonylglycine is a metabolite produced by Aspergillus and possibly other fungal species in the GI tract.

Glutaric acid is made from lysine & tryptophan via alphaketo-adipic acid.

- Elevated in the genetic diseases glutaric academia types I and II.
- Moderate increases may be due to deficiencies in riboflavin and coenzyme Q10, or celiac disease.
- Moderate increases are common in autism possibly due to defective vitamin absorption or microbial production in the GI tract.

Normal values rule out genetic causes of significantly elevated urinary oxalic acid.

Indicator of genetic disease of oxalate metabolism called Hyperoxaluria type I due to a deficiency in the enzyme activity of alanine glyoxylate amino transferase (AGT).

Hippuric acid is a conjugate (=a compound formed by the joining of two or more compounds) of glycine and benzoic acid formed in the liver.

Most hippuric acid in urine is derived from microbial breakdown of chlorogenic acid to benzoic acid.

Homogentisic acid is a breakdown product of 4-Hydroxyphenylpyruvic Acid (4-HPPA). 

Elevated in the genetic disease homogentisic aciduria (alkaptonuria).

Homovanillate (aka Homovanillic Acid) is a dopamine metabolite.

Homovanillate and Vanilmandelate are breakdown products from neurotransmitters involved in hormone and nerve impulse transmission, called catecholamines.

HPHPA is a clostridia metabolite and dysbiosis marker and stands for 3-(3-hydroxyphenyl)-3-hydroxypropionic acid.

The Organic Acids Test measures levels of HVA (homovanillic acid) and VMA (vanillylmandelic acid), the metabolites of the neurotransmitters, dopamine and epinephrine/norepinephrine. It also measures the ratio of the two metabolites.

HVA and DOPAC are the major metabolites of dopamine. HVA stands for Homovanillic acid and DOPAC stands for Dihydroxyphenylacetic.

Kynurenic Acid is product of the metabolism of L-Tryptophan and appears in urine in Vitamin B6 deficiencies. Your body needs vitamin B6 (pyridoxine) to utilize amino acids derived from dietary protein.

Formed from pyruvate in anaerobic or oxygen-starved (hypoxic) conditions to allow for ongoing production of ATP.

Malic Acid is involved in the citric acid cycle (aka. Krebs cycle). The citric acid cycle is a series of reactions that occur in the mitochondrion to generate chemical energy that fuels the metabolism.

Malonic acid is found to be associated with malonyl-CoA decarboxylase deficiency, which is an inborn error of metabolism. The name “Malonic” originates from Latin malum, meaning apple. Malonic acid is the archetypal example of a competitive inhibitor: it acts against succinate dehydrogenase (complex II) in the respiratory electron transport chain. 

Mandelic acid is the major metabolite of styrene. Styrene (vinylbenzene) is used as an intermediate in plastic synthesis. Values less than 5 mg/L are due to normal metabolism of phenylalanine or tyrosine.

Methylmalonic acid (MMA) is a substance produced in very small amounts and is necessary for human metabolism and energy production.

Orotic Acid is a sensitive marker of your liver’s capacity to convert toxic ammonia to non-toxic urea that you can excrete. That capacity can be increased by additional arginine. Ammonia toxicity can also be reduced by supplementation with α-ketoglutarate, magnesium, aspartic acid, and glutamic acid. Ammonia impairs brain function, causing difficulty with thinking, fatigue, headaches, and increased food sensitivities.

Oxalic acid may be associated with dysbiosis from Aspergillus, Penicillium, Candida, or high dose vitamin C. If yeast or fungal markers are elevated, antifungal therapy may reduces oxalates. Also associated with anti-freeze (ethylene glycol) poisoning.

Pantothenic acid is an essential B vitamin (=Vitamin B5) that is converted to coenzyme A (unrelated to vitamin A). Coenzyme A is needed for the synthesis of fatty acids, cholesterol, and acetyl choline and is also needed for the Krebs cycle and fatty acid catabolism.

Phosphoric acid is a marker of vitamin D and calcium. This marker indicates whether vitamin D receptors are activated. If phosphoric acid is low, then the person is likely vitamin D and/or calcium deficient. Low levels can be due to low phosphate consumption, low digestive juice production, or deficiencies in vitamin D, vitamin K2, or magnesium.

Pyruvic Acid feeds into the citric acid cycle & converts into acetyl CoA. Pyruvate is formed from carbohydrate via glucose or glycogen & secondarily from fats (glycerol) & glycogenic amino acids.

Quinolinic acid is a neurotoxic substance produced by our own bodies and a metabolite of tryptophan.

A high ratio of quinolinic acid to the tryptophan metabolite, 5-hydroxyindoleacetic acid, indicates excessive inflammation due to recurrent infections, excessive tryptophan intake, immune overstimulation, excessive adrenal production of cortisol, or excessive exposure to phthalates.

Increased urinary products of the omega fatty acid metabolism pathway may be due to carnitine deficiency, fasting, or increased intake of triglycerides from coconut oil, or some infant formulas.

Suberic Acid, Adipate, and Ethylmalonate elevations can indicate that you may need additional carnitine and/or vitamin B2 to assist your cells in converting fats into energy efficiently.

Succinate (or succinic acid) is an important metabolite that is involved in several chemical processes in the body.

Breakdown product of hyaluronic acid; also found in some foods.

Marker for exposure to certain fungal contamination in foods.

Metabolite of epinephrine and norepinephrine. Often elevated due to stress induced catecholamine output or lead toxicity.