Arylsulfatase A, Leukocytes
Label Mnemonic: ARSAW
Epic Lab Code: LAB2622
Downtime Form: A-1a Miscellaneous Request
Commercial Mail-out Laboratory
5231 RCP
356-8593
Specimen(s):
Whole Blood
Specimen Instructions:
Specimen must arrive within 96 hours of draw to be stabilized. Draw specimen Monday through Thursday only and not the day before a holiday. Specimen should be drawn and packaged as close to shipping time as possible.
Collection Medium:
Yellow top tube 8.5 mL (ACD solution A)
Minimum:
5 mL whole blood
Turn Around Time:
8 days upon receipt at reference laboratory
Reference Range:
> or =62 nmol/h/mg
Interpretive Data:
Decreased enzyme levels indicate an individual is affected with metachromatic leukodystrophy (MLD). Note that individuals with pseudoarylsulfatase A deficiency can have results in this range, but are otherwise unaffected with MLD.

Abnormal results should be confirmed using CTSA, Ceramide Trihexosides and Sulfatides, Urine. If molecular confirmation is desired, consider molecular genetic testing of the ARSA gene.
Comments:
Please print, complete and submit the Informed Consent for Genetic Testing from Mayo Medical Laboratories with the specimen and the A-1a Miscellaneous Request or Epic Req.

Cautions:
This test is not reliable in identifying carriers due both to analytical variation and unusual genetic variants.

Individuals with pseudodeficiency of arylsulfatase A may have decreased enzyme activity and are not clinically affected with metachromatic leukodystrophy.

Arylsulfatase A is also deficient in individuals with multiple sulfatase deficiency.

This disorder is distinct from conditions caused by deficiencies of arylsulfatase B (Maroteaux-Lamy disease) and arylsulfatase C (steroid sulfatase deficiency).
Methodology:
Colorimetric Enzyme Assay
CPT Code:
82657
 
See also:
Leukocyte Lysosomal Enzyme Screen, Whole Blood