Test Catalog

Test Id : C5DCU

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C5-DC Acylcarnitine, Quantitative, Random, Urine

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Overview

Test Catalog

Useful For
Suggests clinical disorders or settings where the test may be helpful

Evaluation of patients with an abnormal newborn screen showing elevations of glutarylcarnitine

 

Diagnosis of glutaric aciduria type 1 deficiency

Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request

Elevated glutarylcarnitine (C5-DC) in plasma or newborn screening blood spots is due to glutaric aciduria type 1 (GA-1), also known as glutaric acidemia type 1.

 

Urine C5-DC is a biochemical marker of GA-1 that appears to be elevated even in low excretors, who are affected patients with normal levels of glutaric acid in urine.

Method Name
A short description of the method used to perform the test

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

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

C5-DC Acylcarnitine, QN, U

Aliases
Lists additional common names for a test, as an aid in searching

Acylcarnitines, urine

GA 1

GA1

GCDH (Glutaryl-CoA Dehydrogenase) Deficiency

Glutaric Aciduria 1 (GA1) (GA 1)

Glutaric Aciduria Type 1

Glutaryl-CoA Dehydrogenase (GCDH) Deficiency

GAI

GA I

Glutarylcarnitine

Specimen Type
Describes the specimen type validated for testing

Urine

Ordering Guidance

This second-tier test is used specifically to evaluate a newborn screening elevation of glutarylcarnitine and must not be ordered with either C4U / C4 Acylcarnitine, Quantitative, Random, Urine or C5OHU / C5-OH Acylcarnitine, Quantitative, Random, Urine.

 

For general screening for metabolic disorders, see OAU / Organic Acids Screen, Random, Urine; ACRN / Acylcarnitines, Quantitative, Plasma; and AAQP / Amino Acids, Quantitative, Plasma.

Necessary Information

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

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

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

Specimen Volume: 5 mL

Collection Instructions:

1. Collect a random urine specimen.

2. Freeze specimen immediately.

Forms

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.

1 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

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

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) 7 days
Refrigerated 24 hours

Useful For
Suggests clinical disorders or settings where the test may be helpful

Evaluation of patients with an abnormal newborn screen showing elevations of glutarylcarnitine

 

Diagnosis of glutaric aciduria type 1 deficiency

Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request

Elevated glutarylcarnitine (C5-DC) in plasma or newborn screening blood spots is due to glutaric aciduria type 1 (GA-1), also known as glutaric acidemia type 1.

 

Urine C5-DC is a biochemical marker of GA-1 that appears to be elevated even in low excretors, who are affected patients with normal levels of glutaric acid in urine.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

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. Diagnostic testing by acylcarnitine analysis, including the evaluation of C5DC in urine, is helpful to determine if a patient has GA1.(1) Urinary excretion of C5-DC is a specific biochemical marker of GA-1 that appears to be elevated even in low excretors, those patients who are affected but have 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 and Genomics newborn screening work group published diagnostic algorithms for the follow-up of infants who had a positive newborn screening result. For more information, see the Practice Resources: ACT Sheets and Algorithms at www.acmg.net.

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.

<1.54 millimoles/mole creatinine

Interpretation
Provides information to assist in interpretation of the test results

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

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

The results of urine acylcarnitines typically are not informative when the patient is receiving L-carnitine supplements.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Miller MJ, Cusmano-Ozog K, Oglesbee D, Young S; ACMG Laboratory Quality Assurance Committee: Laboratory analysis of acylcarnitines, 2020 update: a technical standard of the American College of Medical Genetics and Genomics (ACMG). Genet Med. 2021;23(2):249-258

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(3):677-694

3. Guenzel AJ, Hall P, Scott AI, et al. The low excretor phenotype of glutaric acidemia type I is a source of false negative newborn screening results and challenging diagnoses. JIMD Rep.2021;60(1)67–74

Method Description
Describes how the test is performed and provides a method-specific reference

Acylcarnitines, including glutarylcarnitine, are determined in urine by flow injection analysis tandem mass spectrometry using acetyl-d3-carnitine, propionyl-d3-carnitine, butyryl-d3-carnitine, octanoyl-d3-carnitine, dodecanoyl-d3-carnitine, and palmitoyl-d3-carnitine as internal standards. The supernatant is evaporated and the residue treated with n-butanolic hydrochloric acid yielding the acylcarnitines for analysis as their n-butyl esters.(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(2):137-143; Miller MJ, Cusmano-Ozog K, Oglesbee D, Young S; ACMG Laboratory Quality Assurance Committee. Laboratory analysis of acylcarnitines, 2020 update: a technical standard of the American College of Medical Genetics and Genomics (ACMG). Genet Med. 2021;23(2):249-258)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

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, Wednesday, Friday

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.

2 to 5 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

1 month

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

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.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their account representative. For assistance, contact Customer Service.

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.

82017

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
C5DCU C5-DC Acylcarnitine, QN, U 54279-5
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.
88831 C5-DC Acylcarnitine, QN, U 54279-5
28126 C5-DC Interpretation 59462-2
34470 Reviewed By 18771-6

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports