Arylsulfatase A, Urine
EPIC: LAB5947, Beaker: XARSA, Mayo: ARSU
Please refer to the Specimen Collection Manual for instructions on 24-Hour Urine Collection:
Specimen Collection Criteria
Collect: 24-hour urine sample with no preservative.
- Critical refrigerated. 24-hour urine specimen MUST be kept on ice or refrigerated throughout collection and transport.
- Include start and end dates and times for the collection period on the specimen container.
Urine Preservative Options
6N Hydrochloric Acid
Boric Acid (10g)
50% Acetic Acid
Physician Office/Draw Specimen Preparation
Maintain specimens refrigerated (2-8°C or 36-46°F) prior to transport.
Preparation for Courier Transport
Transport: Entire 24-hour urine collection, refrigerated (2-8°C or 36-46°F).
Specimens not collected and processed as indicated.
Measure total volume of 24-hour urine specimen. Record total volume and collection start and end dates and times in the LIS system. Aliquot 6.0 mL from the well-mixed 24-hour urine collection. (Minimum: 2.5 mL)
Specimen Stability for Testing:
Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): 14 days
Frozen (-20°C/-4°F or below): Unacceptable
Specimen Storage in Department Prior to Disposal:
Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.
Sent to Mayo Medical Laboratory, Rochester, MN.
Results available within 10-17 days.
Greater than 19 nmol/h/mL.
Colorimetric, Enzyme Assay.
Arylsulfatase A is a lysosomal enzyme which exhibits markedly decrease activity in patients with metachromatic leukodystrophy, an inherited metabolic disorder. This results in the accumulation of galactosyl sulfatides in the CNS, peripheral nerves, and organs.
Determination of arylsulfatase A in the urine can be used as a screening test for metachromatic leukodystrophy since affected patients contain decreased urinary arylsulfatase A activity.
Metachromatic leukodystrophy (MLD) is an autosomal recessive demyelinating disorder caused by deficiency of arylsulfatase A, an enzyme responsible for degradation of cerebroside sulfate, a major constituent of myelin lipids. Neurologic signs include ataxia, optic atrophy, mental deterioration, spasticity, and coma, though age of onset can vary from infancy to adulthood, correlating to some degree with amount of residual enzyme activity. A variety of mutations are characterized in the gene, allowing for molecular diagnosis to supplement nerve conduction studies, sural nerve biopsy, and enzymatic assays.
Send Outs Laboratory – RO
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