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Test ID NBLD0735 Glucotetrasaccharides, Random, Urine

Useful For

Diagnosing Pompe disease, when used in conjunction with acid alpha-glucosidase enzyme activity assays and molecular genetic analysis of the GAA gene

 

Monitoring patients with Pompe disease on enzyme replacement therapy

 

May support the diagnosis and monitoring of other glycogen storage disorders; however, glucotetrasaccharide (Glc4) excretion appears to be less consistently elevated in glycogen storage disorders other than Pompe disease

 

This test is not useful for carrier screening.

Specimen Type

Urine


Ordering Guidance


 



Additional Testing Requirements


When requested for the diagnosis of Pompe disease (glycogen storage disorder type II), urine glucotetrasaccharide concentrations need to be interpreted in light of the clinical presentation and other laboratory test results, such as blood creatine kinase, alpha-glucosidase (GAA) activity, and GAA genotype.



Necessary Information


1. Patient's age is required.

2. Reason for testing is required.



Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Container/Tube: Plastic, 5-mL urine tube

Specimen Volume: 3 mL

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
Urine Frozen (preferred) 87 days
  Refrigerated  28 days
  Ambient  14 days

Reject Due To

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

Day(s) Performed

Wednesday

Report Available

4 to 10 days

Method Name

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

Reporting Name

Glucotetrasaccharides, U

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Secondary ID

64174

Testing Algorithm

For more information see Newborn Screen Follow-up for Pompe Disease

Reference Values

≤14 months: ≤14.9 mmol/mol Cr

≥15 months: ≤4.0 mmol/mol Cr

Test Classification

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

82542

82570