Hexosaminidase A and B, Blood (Referred Out) - Saskatoon
Discipline
Biochemistry
Overview
Description
- This test can be used as a 1st tier test for patients with a clinical suspicion of Tay-Sachs/Sandhoff Disease.
- The enzyme activity is determined using plasma specimen. This test might not be optimal for individuals who are pregnant, using oral contraceptives, or have severe liver or autoimmune disease.
Test ordering requirements
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
Alias
- Tay-Sachs Disease
- Sandhoff Disease
- Mucolipidoses
Specimen Information
Specimen types accepted
- Plasma
Specimen collection container
- Preferred collection container: Dark Green (Lithium Heparin) 4.0mL
- Alternative collection container: Dark Green (Sodium Heparin) 4.0mL
Required volume
- Optimal volume: Two full 4.0 mL collection tubes
- Minimum/pediatric volume: 4.0 mL whole blood
Transport and stability
- Store plasma frozen
- Ship plasma frozen to referral laboratory
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 information
- Results should be interpreted in the context of patient history, clinical findings and other laboratory data.
Performance
Methodology
- Quantifies levels of total and beta-hexosaminidase via the 4-methylumbelliferyl substrate
Days/times performed
Availability |
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Testing site |
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Maximum laboratory time
- 2 week turnaround time by referral laboratory
Other information
Additional comments
- Tay Sachs disease, an autosomal recessive lysosomal storage disorder, is caused by deficiency of hexosaminidase A. Deficient enzyme activity of hexosaminidase A leads to accumulation of GM2 ganglioside and thus destructs neurons in the brain and spinal cord. At the age of 3-6 months, developmental regression becomes evident. Clinical symptoms include hypotonia, inattentiveness, loss of motor skills, hearing loss and vision loss.
- Sandhoff disease results from deficiencies in hexosaminidase A and B, and it cannot clinically be distinguishable from Tay Sachs Disease.
- Hexosaminidase enzyme activity is considered as the gold standard to confirm a diagnosis of Tay-Sachs/Sandhoff disease.
Last Updated: October 9, 2024