Test Catalog

Test Id : AAMSD

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Amino Acids, Maple Syrup Urine Disease Panel, Plasma

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Overview

Test Catalog

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

Follow-up of patients with maple syrup urine disease

 

Monitoring of dietary compliance for patients with maple syrup urine disease

Highlights

This test is appropriate for follow-up and dietary monitoring of patients with maple syrup urine disease.

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

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Portions of this test are covered by patents held by Quest Diagnostics

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

Amino Acid, MSUD Panel, P

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

Allo-Isoleucine

Isoleucine

Leucine

Maple Syrup Urine Disease (MSUD)

MSUD (Maple Syrup Urine Disease)

Valine

Maple Syrup Disease

Branched-chain ketoacid dehydrogenase (BCKDH)

Specimen Type
Describes the specimen type validated for testing

Plasma

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

Patient Preparation: Fasting (overnight preferred, 4 hours minimum). Infants should be drawn just before next feeding (2-3 hours without total parenteral nutrition: TPN if possible).

Collection Container/Tube:

Preferred: Green top (sodium heparin)

Acceptable: Lavender top (EDTA), plasma gel tube, or green top (lithium heparin)

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions:

1. Collect specimen and place on wet ice. Note: Thrombin-activated tubes should not be used for collection.

2. Centrifuge immediately or within 4 hours of collection if specimen is kept at refrigerated temperature.

3. Being careful to ensure that no buffy coat is transferred, aliquot plasma into a plastic vial and freeze.

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.

0.3 mL

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

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

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
Plasma Frozen 14 days

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

Follow-up of patients with maple syrup urine disease

 

Monitoring of dietary compliance for patients with maple syrup urine disease

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

Maple syrup urine disease (MSUD) is an inborn error of metabolism caused by the deficiency of the branched-chain alpha-keto acid dehydrogenase (BCKDH) complex. The BCKDH complex is involved in the metabolism of the branched-chain amino acids (BCAA): isoleucine, leucine, and valine. MSUD can be divided into 5 phenotypes: classic, intermediate, intermittent, thiamine-responsive, and dihydrolipoyl dehydrogenase (E3)-deficient, depending on the clinical presentation and response to thiamin administration. Classic MSUD, the most common and most severe form, presents in the neonate with feeding intolerance, failure to thrive, vomiting, lethargy, and maple syrup odor to urine and cerumen. If untreated, it progresses to irreversible intellectual diabilities, hyperactivity, failure to thrive, seizures, coma, cerebral edema, and possibly death.

 

Age of onset for individuals with variant forms of MSUD is variable and some have initial symptoms as early as 2 years of age. Symptoms include poor growth and feeding, irritability, and developmental delays. These patients can also experience severe metabolic intoxication and encephalopathy during periods of sufficient catabolic stress.

 

MSUD is a panethnic condition but is most prevalent in the Old Order Mennonite community in Lancaster, Pennsylvania with an incidence of 1:760 live births. The incidence of MSUD is approximately 1:185,000 live births in the general population.

 

Treatment of MSUD aims to normalize the concentration of BCAA by dietary restriction of these amino acids. Because BCAA are essential amino acids, the dietary treatment requires frequent adjustment, which is accomplished by regular determination of BCAA and allo-isoleucine concentrations. Orthotopic liver transplantation has been used with success and is an effective therapy for MSUD.

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.

ISOLEUCINE

< or =23 months: 31-105 nmol/mL

2-17 years: 30-111 nmol/mL

> or =18 years: 36-107 nmol/mL

 

LEUCINE

< or =23 months: 48-175 nmol/mL

2-17 years: 51-196 nmol/mL

> or =18 years: 68-183 nmol/mL

 

VALINE

< or =23 months: 83-300 nmol/mL

2-17 years: 106-320 nmol/mL

> or =18 years: 136-309 nmol/mL

 

ALLO-ISOLEUCINE

< or =23 months: <2 nmol/mL

2-17 years: <3 nmol/mL

> or =18 years: <5 nmol/mL

Interpretation
Provides information to assist in interpretation of the test results

The quantitative results of isoleucine, leucine, valine, and allo-isoleucine with age-dependent reference values are reported without added interpretation. When applicable, reports of abnormal results may contain an interpretation based on available clinical interpretation.

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

Reference values are for fasting patients.

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

1. Chuang DT, Shih VE, Max Wynn RR. Maple syrup urine disease (Branched-chain ketoaciduria). In: Valle DL, Antonarakis S, Ballabio A, Beaudet AL, Mitchell GA. eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw Hill; 2019. Accessed October 5, 2022. https://ommbid.mhmedical.com/content.aspx?bookid=2709&sectionid=225084607

2. Frazier DM, Allgeier C, Horner C, et al: Nutrition management guideline for maple syrup urine disease: an evidence- and consensus-based approach. Mol Genet Metab. 2014 Jul;112(3)210-217. doi: 10.1016/j.ymgme.2014.05.006

3. Strauss KA, Puffenberger EG, Morton DH: Maple syrup urine disease. In: RA Pagon, MP Adam, HH Ardinger, et al, eds. GeneReviews[Internet]. University of Washington, Seattle; 2006. Updated April 23, 2020. Accessed October 5, 2022. Available at www.ncbi.nlm.nih.gov/books/NBK1319

4. Diaz VM, Camarena C, de la Vega A, et al: Liver transplantation for classical maple syrup urine disease: Long-term follow-up. J Pediatr Gastroenterol Nutr. 2014 Nov;59(5):636-639. doi: 10.1097/MPG.0000000000000469

5. Blackburn PR, Gass JM, Vairo FPE, et al:. Maple syrup urine disease: mechanisms and management. Appl Clin Genet. 2017 Sep 6;10:57-66. doi: 10.2147/TACG.S125962

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

Quantitative analysis of amino acids is performed by liquid chromatography tandem mass spectrometry (LC-MS/MS) by labeling amino acids present in plasma, urine, and spinal fluid with aTRAQ Reagent 121. Samples are dried and reconstituted with aTRAQ Reagent 113-labeled Standard Mix. Amino acids are separated and detected by LC-MS/MS. The concentrations of amino acids are established by comparison of their ion intensity (121-labeled amino acids) to that of their respective internal standards (113-labeled amino acids).(Unpublished Mayo method)

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 through 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.

3 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

2 weeks

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. This test 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.

82136

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
AAMSD Amino Acid, MSUD Panel, P 94566-7
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.
32446 Valine 94567-5
32447 Isoleucine 94568-3
32448 Leucine 94569-1
32449 Allo-isoleucine 94570-9
32450 Interpretation (AAMSD) 49247-0

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