Organic Acids, Limited, Quantitative, Urine

Overview

  • EPIC Code:
  • LAB2639
  • Soft Test Code:
  • Send Out Test Code:
  • 35820
Alternate Names
  • Organic Acids Limited, Qnt, UR
  • ORLQ
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.


Specimen Collection & Preparation

Specimen Requirements

10.0 mL Urine Non Sterile Yellow Plastic Containers (No preservatives)


Transport And Storage

72 hours Refrigerated
28 days Frozen (transport)


Collection Instructions

Patient age should be included in order

Freeze immediately


Minimum Volume

4.0 mL Urine


Neonatal Volume

Clinical Interpretation

Reference Range:

Refer to Interpretive Results


Methodology:
  • Gas Chromatography / Mass Spectrometry (GC/MS)
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.


Production Schedule

Sites Performed
  • Quest - Chantilly to San Juan Capistrano
Days Performed
Tuesday
Friday
Departments
  • Sendouts - Clinical
Turn Around Time

5 to 7 days


Coding & Compliance

CDM

00913333


CPT Coding

82542, 82570