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Test ID HEX4 Glucotetrasaccharides, Random, Urine

Ordering Guidance


Additional Testing Requirements

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

Necessary Information

Patient's age and reason for testing are required.

Specimen Required

Supplies: Sarstedt 5 mL Aliquot Tube (T914)

Container/Tube: Plastic, 5-mL urine tube

Specimen Volume: 3 mL

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative.

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 Pompe patients 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


Increased accumulation of glycogen in the lysosome is a typical finding due to lack of the lysosomal enzyme acid alpha-glucosidase (GAA). Excess glycogen is degraded to glucotetrasaccharide, which is excreted in urine.


Most individuals with glycogen storage disorder type II (GSD II, Pompe disease) and other glycogen storage disorders excrete glucotetrasaccharides in their urine.


Measuring glucotetrasaccharide in the urine can be helpful when employed in conjunction with GAA enzyme activity assay and molecular genetic analysis of the GAA gene.


Measuring glucotetrasaccharide in the urine of GSD II patients undergoing enzyme replacement therapy (ERT) has been reported as a useful tool for monitoring the effects of treatment.

Testing Algorithm

See Newborn Screen Follow-up for Pompe Disease in Special Instructions.

Method Name

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

Reporting Name

Glucotetrasaccharides, U

Specimen Type


Specimen Minimum Volume

1 mL

Specimen Stability Information

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

Reference Values

≤14 months: ≤14.9 mmol/mol Cr

≥15 months: ≤4.0 mmol/mol Cr

Day(s) Performed


Report Available

7 to 14 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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 US Food and Drug Administration.

CPT Code Information



LOINC Code Information

Test ID Test Order Name Order LOINC Value
HEX4 Glucotetrasaccharides, U 53868-6


Result ID Test Result Name Result LOINC Value
64174 Glucotetrasaccharides, U 53868-6
BG710 Reason for Referral 42349-1
BA2896 Intepretation (HEX4) 59462-2
BA2897 Reviewed By 18771-6

NY State Approved