Test Id : OAUS
Organic Acids Screen, Urine Spot
Useful For
Suggests clinical disorders or settings where the test may be helpful
Diagnosis of inborn errors of metabolism using dried urine specimens
Highlights
This test provides a qualitative report of abnormal levels of organic acids identified via gas chromatography mass spectrometry.
Diagnostic specificity of inborn errors of metabolism via urine organic acids analysis is variable due to factors such as specimen collection when the patient is asymptomatic versus acutely ill, taking dietary supplements, or anabolic versus catabolic status of the patient.
Method Name
A short description of the method used to perform the test
Gas Chromatography Mass Spectrometry (GC-MS)
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
2-Ketoadipic Acid
2-Ketoglutaric Acid
3-OH Dodecanedioic Acid
3-OH Sebacic Acid
4-OH Butyric Acid
Adipic Acid
Alkaptonuria
Canavan Disease
Ethylmalonic Acid (EMA)
Fumaric Acid
GA2
Gamma-Hydroxybutyric (GHB) Acid
Gamma-OH-butyrate
Glutaric Acid
Glycerate
Homogentisic Acid
Isovaleric Acid (IVA)
Lactic Acid
MADD (Multiple Acyl-CoA Dehydrogenase Deficiency)
Malonic Acid
Methylmalonate
Mevalonic Acid
MMA (Methylmalonic Acid)
Multiple Carboxylase Deficiency
N-Acetyl Aspartic Acid
Octenedioic Acid
Pyroglutamic Acid
Pyruvic Acid
Sebacic Acid
Suberic Acid
Succinylacetone
Specimen Type
Describes the specimen type validated for testing
Urine
Ordering Guidance
The preferred screening test for organic acidemias is OAU / Organic Acids Screen, Random, Urine, which should be ordered unless collecting or sending urine is difficult or not feasible.
Necessary Information
1. Patient's age is required.
2. Biochemical Genetics Patient Information (T602) is recommended, but not required, to be filled out and sent with the specimen to aid in the interpretation of test results.
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Supplies: Card-Blood Spot Collection (Filter Paper) (T493)
Collection Container:
Preferred: Blood Spot Collection Card
Acceptable: Whatman Protein Saver 903 paper, PerkinElmer 226 filter paper, Munktell filter paper
Specimen Volume: 1 Filter paper card soaked with urine, typically requires 2 to 3 mL of urine
Collection Instructions
1. Soak a filter paper card with urine, approximately 22 cm(2) in area (typically requires 2 to 3 mL of urine; exact measurement is not important as urine volume will be normalized to creatinine).
Note: Filter paper sample may be collected by dipping the card into a collection cup of urine. Avoid dilute urine if possible.
2. Let urine dry on filter paper at ambient temperature in a horizontal position for a minimum of 3 hours.
3. Do not expose specimen to heat or direct sunlight.
4. Do not stack wet specimens.
5. Keep specimen dry.
Special Instructions
Library of PDFs including pertinent information and forms related to the test
Forms
1. Biochemical Genetics Patient Information (T602)
2. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
2 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Frozen (preferred) | 28 days | FILTER PAPER |
| Ambient | 14 days | FILTER PAPER | |
| Refrigerated | 14 days | FILTER PAPER |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Diagnosis of inborn errors of metabolism using dried urine specimens
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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 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 Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
An interpretive report will be provided.
Interpretation
Provides information to assist in interpretation of the test results
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).
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
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 reflects 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 patients who are not acutely ill.
Urine samples with creatinine values below 10 mg/dL may be too dilute for accurate interpretation.
Toluene should not be used as a preservative as it will interfere with the test.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Lehotay DC, Clarke JT. Organic acidurias and related abnormalities. Crit Rev Clin Lab Sci. 1995;32(4):377-429
2. Ferreira CR, van Karnebeek CDM. Inborn errors of metabolism. In: de Vries LS, Glass HC, eds. Neonatal Neurology. Elsevier; 2019:449-481. Handbook of Clinical Neurology. Vol 162
3. Chapman KA. Practical management of organic acidemias. Trans Sc Rare Dis. 2019;1-12. doi:10.3233/TRD-190039
Method Description
Describes how the test is performed and provides a method-specific reference
Urine collected on filter paper is reconstituted in water and a volume corresponding to 0.25 mg of creatinine is acidified and then extracted with ethyl acetate. After separation and evaporation of the solvent phase, the dry residue is sialylated and analyzed by capillary gas chromatography mass spectrometry. When indicated, oximation of 2-keto acids is performed by reaction with hydroxylamine hydrate.(Sweetman L. Organic acid analysis. In: Hommes FA, ed. Techniques in Diagnostic Human Biochemical Genetics. Wiley-Liss; 1991:143-176; Hoffman GF, Feyh P. Organic acid analysis. In: Blau N, Duran M, Blaskovics ME, Gibson KM, eds. Physician's Guide to the Laboratory Diagnosis of Metabolic Diseases. Springer; 2003:27-44; Cowan T, Pasquali M. Laboratory investigations of inborn errors of metabolism. In: Sarafoglou K, Hoffman GF, Roth KS, eds. Pediatric Endocrinology and Inborn Errors of Metabolism. 2nd ed. McGraw-Hill; 2017:1143)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Monday through Saturday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees :
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
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Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
83919
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| OAUS | Organic Acids Scrn, US | 49287-6 |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| 610707 | Organic Acids Scrn, US | 49287-6 |