Alpha-Glucosidase, Dried Blood Spot (Referred Out) - Saskatoon

Overview

Description

Ordering Recommendations

• All required information on the consent form must be filled out:
  • Physician must sign confirmation of informed and medical necessity for genetic testing
  • Patient must sign the consent before blood collection.
  • Please note that an incomplete form will result in cancellation of the test.

Please download the Lysosomal Storage Disorders Testing Program Consent for Enzymatic and Genetic Testing form and the Lysosomal Storage Disorders Testing Program: Requisition and Consent form from the link in TEST ORDERING REQUIREMENTS (BELOW).

Forms Required

• Requisitions must have specific test indicated
• Miscellaneous Specimen Requisition Form #101878  or SHR Laboratory Medicine Community Laboratory Requisition Form #101064 or Acute Care Phlebotomy Requisition Form #101062
• Roadmap2Rare Lysosomal Storage Requisition and Consent

Alias

• Pompe Disease; acid alpha-glucosidase; acid maltase; GAA; GSD II

Specimen Information

Specimen types accepted

• Whole blood

Specimen collection container

• Preferred Collection Container: Lavender (EDTA) 4.0mL

Required volume

• Optimal Volume: 4 mL whole blood
• Minimum/Pediatric Volume: 1 mL whole blood

Transport and stability

• Whole blood must be received within 24 hours of collection
• Store whole blood at room temperature
• The Lysosomal Storage Disorder Card will be spotted when whole blood received in the lab. 
• Lysosomal Storage Disorder Card should be spotted with whole blood within 24 hours of collection.
• Once spotted, the Lysosomal Storage Disorder Card should be allowed to dry for 3-4 hours and shipped to referral laboratory at ambient temperature.

Rejection criteria

• Specimens received where the proper collection protocols were not followed
• Pathology and Laboratory Medicine Acceptance and Rejection Criteria

Testing Information

Relevant clinical history

• Family history
• Must include diagnosis and/or patient symptoms on the requisition.

Clinical interpretation

• Result interpretation should be correlated with clinical and other laboratory findings.

Performance

Methodology

• Tandem mass spectrometry

Days/times performed

• Referred out by St. Paul’s Hospital Laboratory to PerkinElmer, Pittsburgh, PA

Maximum laboratory time

• 3 week turnaround time by referral laboratory

Other information

• Alpha-glucosidase enzyme activity is determined using dried blood spots.
• Affected patients have minimal or zero enzyme activity; however, some later onset cases might present higher enzyme activity. Appropriate tests, e.g. molecular genetic analysis of GAA gene, might be necessary to determine carrier, disease or pseudodeficiency status.
• Used for the evaluation of patients with a clinical presentation indicative of Pompe Disease, e.g. muscle hypotonia, progressive muscle weakness, respiratory insufficiency or cardiomyopathy.
• Pompe disease, also known as glycogen storage disorder type II (GSD II), is an inherited disorder of glycogen metabolism caused by alpha-glucosidase deficiency.

Last Updated: August 7, 2025