Arylsulfatase A, Blood (Referred Out)- Saskatoon
Discipline
Overview
Description
- Available to be collected only Monday to Wednesday morning, 8:00 -12:00 hours.
Test Ordering Requirements
Forms required
- Requisitions must have specific test indicated
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Miscellaneous Specimen Requisition Form #101878
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or SHR Laboratory Medicine Community Laboratory Requisition Form #101064 or
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Acute Care Phlebotomy Requisition Form #101062
Alias
- Metachromatic Leukodystrophy
- MLD
Specimen Information
Specimen types accepted
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Whole blood
Specimen collection container
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Preferred collection container: Dark Green (Lithium Heparin) 4.0 mL
- Alternative collection container: Dark Green (Sodium Heparin) 4.0 mL
Required volume
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Optimal volume: two full 4 mL collection tubes
- Minimum/pediatric volume: 5 mL whole blood
(Submitting the minimum volume makes it impossible to repeat the test or perform confirmatory/reflex testing. In some situations, a minimum volume may require a second collection.)
Transport and stability
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Whole blood must be sent to the lab without delay
- Collect and keep at room temperature
- Ship whole blood at room temperature to referral laboratory
Rejection criteria
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Specimens received where the proper collection protocols were not followed
- Pathology and Laboratory Medicine Acceptance and Rejection Criteria
Testing Information
Relevant clinical history
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Family history
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Must include diagnosis and/or patient symptoms on the requisition
Clinical interpretation
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Result interpretation should be correlated with clinical and other laboratory findings
Performance
Methodology
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Available upon request
Days/times performed
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Testing Site |
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Maximum laboratory time
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2 week turnaround time by referral laboratory
Other information
Additional comments
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Arylsulfatase A is measured quantitatively. This test can be used as a 1ST tier test for patients suspected with Metachromatic Leukodystrophy (MLD).
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MLD is an autosomal recessive disorder caused by defects in ARSA gene (encodes Arylsulfatase). Arylsulfatase A breaks down sulfatides or sulfate-containing lipids. These lipids make up ~5% of myelin production in the body.
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Pseudo-deficiency ( very low arylsulfatase activity in an otherwise healthy individual) has been reported and is difficult to distinguish from true arylsulfatase deficiency by biochemical test alone.
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Urinary sulfatides test is also useful for the identification of MLD.
Last Updated: October 3, 2024