Arylsulfatase A, Blood (Referred Out) - Saskatoon

Overview

Description

Ordering recommendation ​

• Available to be collected only Monday to Wednesday morning 0800-1200 hours

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

• Metachromatic Leukodystrophy
• MLD

Specimen Information

Specimen types accepted

• Whole blood

Specimen collection container

• Preferred collection container: Dark Green (Lithium Heparin) 4.0 mL
• Alternative collection container: Dark Green (Sodium Heparin) 4.0 mL

Required volume

• 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

• ​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

• 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

• Available upon request

Days/times performed

Availability	Available to be collected only Monday to Wednesday morning 0800-1200 hours
Testing site​	Referred out by St. Paul's Hospital Laboratory to ​Greenwood Genetics Center

 

Maximum laboratory time

Results reporting

• 2 week turnaround time by referral laboratory

Other information

Additional comments

• ​Arylsulfatase A is measured quantitatively. This test can be used as a 1ST tier test for patients suspected with Metachromatic Leukodystrophy (MLD).
• 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.
• 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.
• Urinary sulfatides test is also useful for the identification of MLD.

Last Updated: February 18, 2026