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Organic Acids, Comprehensive, Quantitative, Urine
MessageFREEZE IMMEDIATELY. SHIP FROZEN. DO NOT THAW.
Test Code
35819
Alias/See Also
LAB418
CPT Codes
83918, 82570
Preferred Specimen
10 mL random urine collected in a sterile screw-cap container with no preservative
Minimum Volume
4 mL
Instructions
Sterile screw-cap container. Freeze immediately. Ship frozen. Do not thaw.
Patient age should be included.
Patient age should be included.
Transport Container
Sterile screw-cap container
Transport Temperature
Frozen
Specimen Stability
Room temperature: Unacceptable
Refrigerated: 72 hours
Frozen: 28 days
Refrigerated: 72 hours
Frozen: 28 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Received refrigerated • Samples with pH <2
Methodology
Gas Chromatography/Mass Spectrometry (GC/MS)
Reference Range
See Laboratory Report
Clinical Significance
This test is intended for the diagnosis and monitoring of inherited disorders affecting multiple metabolic pathways.
Organic acidurias are inherited disorders resulting from a deficient enzyme or transport protein. Although most are autosomal recessive disorders, several are X-linked. The more than 60 described organic acidurias affect many metabolic pathways including amino acid metabolism, lipid metabolism, purine and pyrimidine metabolism, the urea cycle, the Krebs cycle and fatty acid oxidation. These disorders are characterized by a wide variety of symptoms such as lethargy, coma, hypotonia, seizures, ataxia, vomiting, failure to thrive, developmental delay, liver disease, neutropenia, thrombocytopenia, osteomalacia and osteoporosis. Severity of presentation is highly variable as is age of onset, and patients may not present with the most characteristic features. Laboratory results commonly indicate metabolic acidosis, increased anion gap, hyperammonemia, hypoglycemia, lactic acidemia, ketosis, or abnormal lipid patterns. Treatment may be based on dietary restrictions and/or supplementation with cofactors (e.g., riboflavin or cobalamin) or conjugating agents (e.g., carnitine or sodium benzoate); however, there is no effective therapy for some of the disorders.
Elevation of one or more organic acids is diagnostic for an organic aciduria; however, elevations should be interpreted in context with clinical findings and/or additional test results. See additional information for a table of selected organic acidurias and associated organic acid elevations. Since many organic acidurias are episodic, the diagnostic efficacy is maximized when the patient is expressing symptoms at the time of specimen collection.
The test will be capable of diagnosing over 30 inherited metabolic defects, and will also allow physicians to determine dietary compliance or the effectiveness of dietary/cofactor therapy for their patients. It can also be used, alone or in conjunction with other tests, to confirm the findings of a positive expanded newborn screen.
Organic acidurias are inherited disorders resulting from a deficient enzyme or transport protein. Although most are autosomal recessive disorders, several are X-linked. The more than 60 described organic acidurias affect many metabolic pathways including amino acid metabolism, lipid metabolism, purine and pyrimidine metabolism, the urea cycle, the Krebs cycle and fatty acid oxidation. These disorders are characterized by a wide variety of symptoms such as lethargy, coma, hypotonia, seizures, ataxia, vomiting, failure to thrive, developmental delay, liver disease, neutropenia, thrombocytopenia, osteomalacia and osteoporosis. Severity of presentation is highly variable as is age of onset, and patients may not present with the most characteristic features. Laboratory results commonly indicate metabolic acidosis, increased anion gap, hyperammonemia, hypoglycemia, lactic acidemia, ketosis, or abnormal lipid patterns. Treatment may be based on dietary restrictions and/or supplementation with cofactors (e.g., riboflavin or cobalamin) or conjugating agents (e.g., carnitine or sodium benzoate); however, there is no effective therapy for some of the disorders.
Elevation of one or more organic acids is diagnostic for an organic aciduria; however, elevations should be interpreted in context with clinical findings and/or additional test results. See additional information for a table of selected organic acidurias and associated organic acid elevations. Since many organic acidurias are episodic, the diagnostic efficacy is maximized when the patient is expressing symptoms at the time of specimen collection.
The test will be capable of diagnosing over 30 inherited metabolic defects, and will also allow physicians to determine dietary compliance or the effectiveness of dietary/cofactor therapy for their patients. It can also be used, alone or in conjunction with other tests, to confirm the findings of a positive expanded newborn screen.
Performing Laboratory
| Quest Diagnostics Nichols Institute-San Juan Capistrano, CA |
| 33608 Ortega Highway |
| San Juan Capistrano, CA 92675-2042 |