Laboratory: Clinical Biochemistry  (METABOLIC)
Test Name:
GLUCOTETRASACCHARIDES (Hex4) - (U)
Test Code: MIS8
Clinical Information:
Alternate Name(s): 
Hex4 Glucotetrasaccharide
Hexose Tetrasaccharide
Pompe Urine Biomarker
Glycogen Storage Disease type II Biomarker
Description:  Diagnosing Pompe disease, when used in conjunction with acid alpha-glucosidase enzyme activity assays and molecular genetic analysis of the GAA gene.
Test Indications: The urine Hex4 assay is used to monitor patients with Pompe Disease (GSD II) on enzyme replacement therapy.
Test Approval Requirements: Biochemical Geneticist Consult Required                                                   F260-11-02 Biochemistry Approval for Test Referral Form
Patient preparation instructions: Prepandrial or fasting samples are recommended to avoid dietary artifacts and enhance sensitivity.
 
Collection Devices:
Specimen Required:
Urine: 3.0 mL
Pediatric Urine: 1.0 mL

Collection Information: No preservative
Special Processing: Store at -20 C and ship frozen.
Specimen Stability: Ambient: 14 days
                                  Refrigerated: 28 days
                                  Frozen: 87 days (recommended)
 
Referral:
Urine: 3.0 mL
Pediatric Urine: 1.0 mL

Shipping & Storage: Send frozen to Metabolic Lab at HSC with the original requisition or clear copy.
Referred Out Location: Mayo Clinical Laboratories- Rochester Main Campus
Test Code: Hex4
Requisition:
Reference Values:
Reference Intervals: < or =14 months: < or =14.9 mmol/mol Cr

                                       > or =15 months: < or =4.0 mmol/mol Cr
 


Method of Analysis: Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Availability:
Within 10 Days
Days Performed: Wednesday
See Also:
More Information:
Additional Information: Hex4 may be elevated in a number of pathological and physiological conditions and is not specific to Pompe disease.