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Test ID: ACYLG Acylglycines, Quantitative, Urine

Reporting Name

Acylglycines, QN, U

Useful For

Biochemical screening of asymptomatic patients affected with 1 of the following inborn errors of metabolism:

-Short chain acyl-CoA dehydrogenase (SCAD) deficiency

-Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency

-Medium-chain 3-ketoacyl-CoA thiolase (MCKAT) deficiency

-Glutaric acidemia type II

-Ethylmalonic encephalopathy

-2-Methylbutyryl-CoA dehydrogenase deficiency

-Isovaleryl-CoA dehydrogenase deficiency

-Glutaryl-CoA dehydrogenase deficiency

Testing Algorithm

The following algorithms are available in Special Instructions:

-Newborn Screening Follow-up for Elevations of C8, C6, and C10 Acylcarnitines (also applies to any plasma or serum C8, C6, and C10 acylcarnitine elevations)

-Newborn Screening Follow-up for Isolated C4 Acylcarnitine Elevations (also applies to any plasma or serum C4 acylcarnitine elevation)

-Newborn Screening Follow-up for Isolated C5 Acylcarnitine Elevations (also applies to any plasma or serum C5 acylcarnitine elevation)

Specimen Type

Urine


Advisory Information


Diagnostic specificity of inborn errors of metabolism via urine acylglycine testing is useful only for the selected inborn errors of metabolism; it is recommended that urine organic acids (OAU / Organic Acids Screen, Urine) be ordered and run simultaneously due to the limited number of metabolites included in this urine acylglycine test.



Necessary Information


1. Patient's age is required.

2. Include family history, clinical condition (asymptomatic or acute episode), diet, and drug therapy information.



Specimen Required


Supplies: Urine Tubes, 10 mL (T068)

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

Specimen Volume: 10 mL

Pediatric: If insufficient collection volume, submit as much specimen as possible in a single container; the laboratory will determine if volume is sufficient for testing.

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative.


Specimen Minimum Volume

4 mL

Specimen Stability Information

Specimen Type Temperature Time
Urine Frozen (preferred) 416 days
  Refrigerated  9 days

Reference Values

Control Values

Results Expressed as mg/g Creatinine

 

Range

Ethylmalonic Acid

0.5-20.2

2-Methylsuccinic Acid

0.4-13.8

Glutaric Acid

0.6-15.2

Isobutyrylglycine

0.00-11.0

n-Butyrylglycine

0.1-2.1

2-Methylbutyrylglycine

0.3-7.5

Isovalerylglycine

0.3-14.3

n-Hexanoylglycine

0.2-1.9

n-Octanoylglycine

0.1-2.1

3-Phenylpropionylglycine

0.00-1.1

Suberylglycine

0.00-11.0

trans-Cinnamoylglycine

0.2-14.7

Dodecanedioic Acid (12 DCA)

0.00-1.1

Tetradecanedioic Acid (14 DCA)

0.00-1.0

Hexadecanedioic Acid (16 DCA)

0.00-1.0

 

Day(s) and Time(s) Performed

Monday, Wednesday, Friday; 8 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

82542

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ACYLG Acylglycines, QN, U 50334-2

 

Result ID Test Result Name Result LOINC Value
21011 Ethylmalonic Acid 13741-4
21012 2-Methylsuccinic acid 13777-8
21013 Glutaric acid 13748-9
21014 Isobutyrylglycine 38360-4
23387 n-Butyrylglycine 27892-9
21015 2-Methylbutyrylglycine 27097-5
21016 Isovalerylglycine 13766-1
23388 n-Hexanoylglycine 13753-9
21017 n-Octanoylglycine 38367-9
23389 3-Phenylpropionylglycine 13793-5
23390 Suberylglycine 13811-5
21018 trans-Cinnamoylglycine 38417-2
21019 Dodecanedioic acid 13732-3
21020 Tetradecanedioic acid 50333-4
21021 Hexadecanedioic acid 50332-6
23414 Interpretation 59462-2
23416 Reviewed By No LOINC Needed

Clinical Information

Acylglycines are glycine conjugates of acyl-CoA species. Acylglycines are normal intermediates of amino acid and fatty acid metabolism; however, in abnormal concentrations acylglycines are biochemical markers of selected inborn errors of metabolism (IEM). Analysis of acylglycines is a useful screening test in the evaluation of patients with a suspected IEM, though additional studies are necessary to establish a diagnosis. The biochemical diagnosis of these disorders is a complex process achieved by multiple tests and their integrated interpretation.

 

Although acylglycines are often ordered in conjunction with organic acids, acylglycine analysis is more sensitive and specific for the identification of asymptomatic patients and those with mild or intermittent biochemical phenotypes that could be missed by organic acid analysis alone. The quantitative analysis of urinary acylglycines is particularly effective for identifying asymptomatic patients affected with disorders including:

-Short chain acyl-CoA dehydrogenase (SCAD) deficiency

-Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency

-Medium-chain 3-ketoacyl-CoA thiolase (MCKAT) deficiency

-Glutaric acidemia type II

-Ethylmalonic encephalopathy

-2-Methylbutyryl-CoA dehydrogenase deficiency

-Isovaleryl-CoA dehydrogenase deficiency

-Glutaryl-CoA dehydrogenase deficiency

Interpretation

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; recommendations for additional biochemical testing and in vitro confirmatory studies (enzyme assay, molecular analysis); name and phone number of key contacts who may provide these studies at Mayo Clinic or elsewhere; and a phone number to reach one of the laboratory directors in case the referring physician has additional questions.

Clinical Reference

1. Rinaldo P: Laboratory diagnosis of inborn errors of metabolism. In Liver Disease in Children. Second edition. Edited by FJ Suchy. Philadelphia, Lippincott, Williams and Wilkins, 2001, pp 171-184

2. Rinaldo P, Hahn SH, Matern D: Inborn errors of amino acid, organic acid, and fatty acid metabolism. In Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Fourth edition. Edited by CA Burtis, ER Ashwood, DE Bruns. WB Saunders Company, 2005, pp 2207-2247

3. Rinaldo P: Organic Acids. In Laboratory Guide to the Methods in Biochemical Genetics. Edited by N Blau, M Duran, KM Gibson. Springer-Verlag Berlin Heidelberg, 2008, pp 137-170

Analytic Time

5 days (not reported on Saturday or Sunday)

Method Name

Gas Chromatography-Mass Spectrometry (GC-MS) Stable Isotope Dilution Analysis

Mayo Medical Laboratories | Genetics and Pharmacogenomics Catalog Additional Information:

mml-biochemical