Acid Alpha-Glucosidase, Leukocytes
GTR Test Accession: Help GTR000603770.2
INHERITED DISEASECARDIOVASCULARMETABOLIC DISEASE ... View more
Last updated in GTR: 2023-04-07
Last annual review date for the lab: 2024-05-28 LinkOut
At a Glance
Diagnosis
Glycogen storage disease, type II
acid alpha-glucosidase
Biochemical Genetics - Enzyme assay: Liquid chromatography-tandem mass spectrometry (LC-MS/MS)
Diagnosis of Pompe disease
Not provided
Establish or confirm diagnosis
Ordering Information
Offered by: Help
Test short name: Help
GAAW
Specimen Source: Help
Who can order: Help
  • Genetic Counselor
  • Health Care Provider
  • Licensed Dentist
  • Licensed Physician
  • Nurse Practitioner
  • Physician Assistant
  • Public Health Mandate
  • Registered Nurse
Lab contact: Help
Gisele (Gessi) Bentz Pino, MS, CGC, Certified Genetic counselor, CGC, Genetic Counselor
biochemicalgenetics@mayo.edu
1-800-533-1710
Contact Policy: Help
Laboratory can only accept contact from health care providers. Patients/families are encouraged to discuss genetic testing options with their health care provider.
How to Order: Help
https://www.mayocliniclabs.com/test-catalog/overview/606267#Specimen
Order URL
Test development: Help
Test developed by laboratory (no manufacturer test name)
Informed consent required: Help
Based on applicable state law
Pre-test genetic counseling required: Help
Decline to answer
Post-test genetic counseling required: Help
Decline to answer
Recommended fields not provided:
Conditions Help
Total conditions: 1
Condition/Phenotype Identifier
Test Targets
Analytes Help
Total analytes: 1
Analyte Associated Condition
Methodology
Total methods: 1
Method Category Help
Test method Help
Instrument *
Enzyme assay
Liquid chromatography-tandem mass spectrometry (LC-MS/MS)
* Instrument: Not provided
Clinical Information
Test purpose: Help
Diagnosis
Target population: Help
Diagnosis of Pompe disease
View citations (2)
  • Lin N, Huang J, Violante S, Orsini JJ, Caggana M, Hughes EE, Stevens C, DiAntonio L, Chieh Liao H, Hong X, Ghomashchi F, Babu Kumar A, Zhou H, Kornreich R, Wasserstein M, Gelb MH, Yu C. Liquid Chromatography-Tandem Mass Spectrometry Assay of Leukocyte Acid α-Glucosidase for Post-Newborn Screening Evaluation of Pompe Disease. Clin Chem. 2017;63(4):842-851. doi:10.1373/clinchem.2016.259036. Epub 2017 Feb 14. PMID: 28196920.
  • Leslie N, Bailey L: Pompe disease. In: Adam MP, Ardinger HH, Pagon RA, et al. GeneReviews [Internet]. University of Washington, Seattle; 2007. Updated May 11, 2017. Accessed March 23, 2022. Available at www.ncbi.nlm.nih.gov/books/NBK1261/
Recommended fields not provided:
Technical Information
Test Procedure: Help
The specimens are incubated with a mix of substrate and internal standard for acid alpha-glucosidase and alpha-galactosidase (GLA). The reaction is then stopped using acetonitrile, centrifuged, and a portion of the supernatant is prepared for analysis by liquid chromatography-tandem mass spectrometry. GLA is included to verify sample integrity.(Unpublished Mayo method)
Availability: Help
Tests performed
Entire test performed in-house
Analytical Validity: Help
Recovery was used to assess accuracy; the acceptance criteria were met with coefficients of linear regression (R2) of 0.9998 and slope of 0.9979 for GAA. Intra assay precision was performed at 3 levels: CV results ranged from 3%-6% (N=20 each). Inter assay precision was performed at 3 levels: CV results … View more
Assay limitations: Help
Pseudodeficiency results in low measured acid alpha-glucosidase activity, but it is not consistent with Pompe disease. Enzyme levels may be normal in individuals receiving enzyme replacement therapy.
Proficiency testing (PT):
Is proficiency testing performed for this test? Help
Yes

Method used for proficiency testing: Help
Intra-Laboratory

Description of PT method: Help
Intra-laboratory alternative assessment of performance through quality control or patient blind testing

Description of internal test validation method: Help
This test was laboratory developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements.
Recommended fields not provided:
Regulatory Approval
FDA Review: Help
Category: FDA exercises enforcement discretion
Additional Information

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