Organic Acids Screen, Urine (OAU)

Test Code: ORGACID

Overview
Ordering
Specimen
Performing
Clinical/Interpretive
Contacts
Coding

Synonyms/Keywords

Lactic, Pyruvic, 3-OH Propionic, 3-OH Butyric, 3-OH Isobutyric, Acetoacetic, 2-Methyl 3-OH Butyric, 3-OH Isovaleric, 2-OH Isovaleric, Malonic, MMA, GHB, 4-OH Butyric, Ethylene Glycol, 2-Ketoisovaleric, 2-Methyl Acetoacetic, Ethylmalonic, Succinic, Fumaric, Uracil, Thymine, Trans-3-hydroxyhexenoic, Trans-5-hydroxyhexenoic, Erythro-2,3-dihydroxy 2-methylbutyric, Mevalonic, Isobutyrylglycine, Glutaric, 3-Methylglutaconic, Propionylglycine, 2-Methylbutyrylglycine, Adipic, 2-Ketoglutaric, Isovalerylglycine, 3-OH 3-Methylglutaric, 4-OH 6-methyl 2-pyrone, 4HMP, Malic, Pyroglutamic, 5-Oxoproline, 3-Methylcrotonylglycine, Tiglylglycine, 2-OH Glutaric, 3-OH Glutaric, Succinylacetone, Hexanoylglycine, N-Acetylaspartic, 2-OH Adipic, Octenedioic, Suberic, 2-Ketoadipic, 2-Oxoadipic, Orotic, Hippuric, Pyrrole-2-Carboxyglycine, Homogentisic, Methylcitric, Sebacic, Vanillylmandelic, VMA, Homovanillic, HVA, Hydantoin 5-propionic, Phenylpropionylglycine, Vanillyllactic, Vanillactic, Suberylglycine, Vanillylpyruvic, N-Acetylvanilalanine, Hawkinsin, Tyrosinemia, Phenylketonuria, Alkaptonuria, Maple Syrup Urine Disease, Barth Syndrome, Costeff Syndrome, E3 Deficiency, MCAD, SBCAD, Beta-Ketothiolase Deficiency, Multiple Carboxylase Deficiency, SCAD, 3HMG-CoA Synthase Deficiency, Dihydropyrimidine Dehydrogenase Deficiency, Neuroblastoma, Glutathione Synthetase Deficiency, SSADHD, Ethylmalonic Encephalopathy, MADD, Multiple Acyl-CoA Dehydrogenase Deficiency, Fumarase Deficiency, AADC, HIBCH, ECHS1, Dicarboxylic Aciduria, Canavan Disease, Hyperprolinemia Type II, Ornithine Transcarbamylase Deficiency, OTC, Aminoacylase Deficiency, Acids, Organic Acids Screen, Random, Urine, U ORGACID

Useful For

Diagnosis of inborn errors of metabolism

Specimen Requirements

Specimen Type	Preferred Container/Tube	Acceptable Container/Tube	Specimen Volume	Specimen Minimum Volume (allows for 1 repeat)	Pediatric Minimum Volume (no repeat)
Urine (no preservative)	Plastic, 10 mL urine tube		10 mL	4 mL	If insufficient collection volume, submit as much specimen as possible in a single container; the laboratory will determine if volume is sufficient for testing.

Collection Processing Instructions

1. Collect a random urine specimen.

2. No preservative.

Additional Information:

1. Patient's age is required.

2. Include family history, clinical condition (asymptomatic or acute episode), diet, and drug therapy information.

Specimen Stability Information

Specimen Type	Temperature	Time
Urine	Frozen (preferred)	416 days
Urine	Refrigerated	14 days

Rejection Criteria

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Interference

The diagnostic specificity of organic acid analysis under acute and asymptomatic conditions may vary considerably.

Informative profiles may not always be detected in disorders where the excretion of diagnostic metabolites is a reflection of the residual activity of the defective enzyme, the dietary load of precursors, and the anabolic/catabolic status of a patient.

In some cases, methods of higher specificity and sensitivity such as acylcarnitine and acylglycine analysis can effectively overcome the limitations of standard organic acid analysis for the investigation of non-acutely ill patients.

Performing Laboratory Information

Performing Location	Day(s) Test Performed	Report Available	Methodology/Instrumentation
Mayo Clinic Laboratories	Monday through Saturday	3 to 5 days	Gas Chromatography-Mass Spectrometry (GC-MS)

Reference Lab

Mayo Clinic Laboratories

Test Information

Organic acids occur as physiologic intermediates in a variety of metabolic pathways. Organic acidurias are a group of disorders in which one or more of these pathways are blocked, resulting in a deficiency of normal products and an abnormal accumulation of intermediate metabolites (organic acids) in the body. These excess metabolites are excreted in the urine.

The incidence of individual inborn errors of organic acid metabolism varies from 1 in 10,000 to greater than 1 in 1,000,000 live births. Collectively, their incidence approximates 1 in 3000 live births. This estimate, however, does not include other inborn errors of metabolism (ie, amino acid disorders, urea cycle disorders, congenital lactic acidemias) for which diagnosis and monitoring may also require organic acid analysis. If all possible disease entities were included, the incidence of conditions where informative organic acid profiles could be detected in urine is likely to approach 1 in 1000 live births.

Organic acidurias typically present with either an acute life-threatening illness in early infancy or unexplained developmental delay with intercurrent episodes of metabolic decompensations in later childhood. A situation of severe and persistent metabolic acidosis of unexplained origin, elevated anion gap, and severe neurologic manifestations, such as seizures, should be considered strong diagnostic indicators of one of these diseases. The presence of ketonuria, occasionally massive, provides an important clue toward the recognition of disorders, especially in the neonatal period. Hyperammonemia, hypoglycemia, and lactic acidemia are frequent findings, especially during acute episodes of metabolic decompensations.

Reference Range Information

Interpretive report

Interpretation

When no significant abnormalities are detected, the organic acid analysis is reported and interpreted in qualitative terms only. When abnormal results are detected, a detailed interpretation is given, including an overview of the results and of their significance, a correlation to available clinical information, elements of differential diagnosis, and recommendations for additional biochemical testing, and in vitro confirmatory studies (enzyme assay, molecular analysis).

Outreach CPTs

CPT	Modifier (if needed)	Quantity	Description	Comments
83919

Synonyms/Keywords

Ordering Applications

Ordering Application	Description
Cerner	Organic Acids Screen, Urine (OAU)

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