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Test ID: C5DCU C5-DC Acylcarnitine, Quantitative, Urine

Reporting Name

C5-DC Acylcarnitine, QN, U

Useful For

Evaluation of patients with an abnormal newborn screen showing elevations of C5-DC

 

Diagnosis of glutaric aciduria type 1 deficiency

Specimen Type

Urine


Necessary Information


Include patient's age, family history, clinical condition (asymptomatic or acute episode), diet, and drug therapy information.

Specimen Required


Patient Preparation: If clinically feasible, discontinue L-carnitine supplementation at least 72 hours before specimen collection.

Supplies: Urine Tubes, 10 mL (T068)

Collection Container/Tube: Clean, plastic urine collection container

Submission Container/Tube: Plastic, 10-mL urine tube (T068)

Specimen Volume: 5 mL

Collection Instructions:

1. Collect a random urine specimen.

2. Freeze specimen immediately.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
Urine Frozen (preferred) 7 days
  Refrigerated  24 hours

Day(s) and Time(s) Performed

Monday, Wednesday, Friday; 8:00 a.m.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

82017

LOINC Code Information

Test ID Test Order Name Order LOINC Value
C5DCU C5-DC Acylcarnitine, QN, U In Process

 

Result ID Test Result Name Result LOINC Value
88831 C5-DC Acylcarnitine, QN, U 54279-5
28126 C5-DC Interpretation 59462-2
34470 Reviewed By No LOINC Needed

Clinical Information

An isolated elevation of glutarylcarnitine (C5-DC) in plasma or newborn screening blood spots is related to a diagnosis of glutaric aciduria type 1 (GA-1), also known as glutaric acidemia type 1. GA-1 is caused by a deficiency of glutaryl-CoA dehydrogenase. Urinary excretion of C5-DC is a specific biochemical marker of GA-1 that appears to be elevated even in low excretors, affected patients with normal levels of glutaric acid in urine.

 

GA-1 is characterized by bilateral striatal brain injury leading to dystonia, often a result of acute neurologic crises triggered by illness. Many affected individuals also have macrocephaly. Dietary treatment and aggressive interventions during time of illness are recommended to try to prevent or minimize neurologic injury, which is most likely to occur in infancy and early childhood. Prevalence is approximately 1 in 100,000 individuals.

 

The American College of Medical Genetics (ACMG) newborn screening work group published diagnostic algorithms for the follow-up of infants who had a positive newborn screening result. For more information, see http://www.acmg.net.

Interpretation

Elevated excretion of C5-DC is a specific biochemical marker of glutaric aciduria type 1 that is elevated in affected patients, apparently even in low excretors or those affected individuals with normal levels of glutaric acid in urine.

Clinical Reference

1. Tortorelli S, Hahn SH, Cowan TM, et al: The urinary excretion of glutarylcarnitine is an informative tool in the biochemical diagnosis of glutaric acidemia type I. Mol Genet Metab 2005;84:137-143

2. Kolker S, Christensen E, Leonar JV, et al: Diagnosis and management of glutaric aciduria type I-revised recommendations. J Inherit Metab Dis 2011:34:677-694

Analytic Time

2 days (not reported on Sunday)

Method Name

Flow Injection Analysis-Tandem Mass Spectrometry (FIA-MS/MS)

Forms

New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.

Mayo Medical Laboratories | Genetics and Pharmacogenomics Catalog Additional Information:

mml-biochemical