Test Id : AAMSD
Amino Acids, Maple Syrup Urine Disease Panel, Plasma
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.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
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
Ordering Guidance
Body fluids are not acceptable specimens for this test.
For testing urine specimens, order AAPD / Amino Acids, Quantitative, Random, Urine.
For testing spinal fluid specimens, order AACSF / Amino Acids, Quantitative, Spinal Fluid.
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: Patient should fast a minimum of 4 hours; infants should have specimen collected before next feeding (2-3 hours without total parenteral nutrition if possible).
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Green top (sodium 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
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.
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 disabilities, 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 particularly 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
<24 months: 23-149 nmol/mL
2-17 years: 26-150 nmol/mL
> or =18 years: 29-153 nmol/mL
Leucine
<24 months: 59-213 nmol/mL
2-17 years: 51-216 nmol/mL
> or =18 years: 79-217 nmol/mL
Valine
<24 months: 94-382 nmol/mL
2-17 years: 111-367 nmol/mL
> or =18 years: 134-357 nmol/mL
Allo-isoleucine
<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 24, 2024. https://ommbid.mhmedical.com/content.aspx?bookid=2709§ionid=225084607
2. Strauss KA, Puffenberger EG, Morton DH: Maple syrup urine disease. In: MP Adam, Feldman J, Mirzaa GM, et al, eds. GeneReviews[Internet]. University of Washington, Seattle; 2006. Updated April 23, 2020. Accessed October 24, 2024. Available at www.ncbi.nlm.nih.gov/books/NBK1319
3. 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;59(5):636-639. doi:10.1097/MPG.0000000000000469
4. Blackburn PR, Gass JM, Vairo FPE, et al. Maple syrup urine disease: mechanisms and management. Appl Clin Genet. 2017;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). Patient samples are combined with isotopically labeled internal standard. Following protein precipitation, the supernatant is subjected to hydrophilic interaction liquid chromatography for the separation of isomers with MS/MS detection of the underivatized amino acids.(Unpublished Mayo method)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
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.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
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.
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 |