Test Code ARSAW Arylsulfatase A, Leukocytes
Reporting Name
Arylsulfatase A, LeukocytesUseful For
Preferred enzymatic test for detection of arylsulfatase A deficiency
This test is not suitable for carrier detection.
Performing Laboratory
Mayo Clinic Laboratories in RochesterSpecimen Type
Whole Blood ACDShipping Instructions
For optimal isolation of leukocytes, it is recommended the specimen arrive refrigerated within 6 days of collection to be stabilized. Collect specimen Monday through Thursday only and not the day before a holiday. Specimen should be collected and packaged as close to shipping time as possible.
Specimen Required
Container/Tube:
Preferred: Yellow top (ACD solution B)
Acceptable: Yellow top (ACD solution A)
Specimen Volume: 6 mL
Collection Instructions: Send specimen in original tube. Do not aliquot.
Specimen Minimum Volume
5 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Whole Blood ACD | Refrigerated (preferred) | 6 days | YELLOW TOP/ACD |
Ambient | 6 days | YELLOW TOP/ACD |
Special Instructions
Reference Values
≥62 nmol/h/mg
Note: Results from this assay may not reflect carrier status because of individual variation of arylsulfatase A enzyme levels. Low normal values may be due to the presence of pseudodeficiency or carrier alleles. Patients with these depressed levels may be phenotypically normal.
Day(s) Performed
Preanalytical processing: Monday through Saturday
Assay performed: Tuesday
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82657
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
ARSAW | Arylsulfatase A, Leukocytes | 24078-8 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
8779 | Arylsulfatase A, Leukocytes | 24078-8 |
32437 | Interpretation | 59462-2 |
32438 | Reason for referral | 42349-1 |
32439 | Reviewed by | 18771-6 |
Interpretation
Reduced levels of arylsulfatase A are seen in patients with metachromatic leukodystrophy (MLD), however some patients with MLD may have normal results by this method.
Individuals with pseudodeficiency of arylsulfatase A can have results in the affected range but are otherwise unaffected with MLD.
Abnormal results and/or clinical suspicion should be confirmed using CTSU / Ceramide Trihexosides and Sulfatides, Random, Urine. If molecular confirmation is desired, consider molecular genetic testing of ARSA (CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies; specify Gene List ID: IEMCP-WHFH2K).
Clinical Reference
1. Gieselmann V, Ingeborg KM: Metachromatic leukodystrophy. In: Valle D, Antonarakis S, Ballabio A, Beaudet A, Mitchell GA, eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill; 2019. Accessed March 29, 2021. Available at https://ommbid.mhmedical.com/content.aspx?sectionid=225546629
2. Gomez-Ospina N: Arylsulfatase A deficiency. In: Adam MP, Ardinger HH, Pagon RA, et al, eds. GeneReviews [Internet]. University of Washington, Seattle; Updated April 30, 2020. Accessed March 29, 2021. Available at www.ncbi.nlm.nih.gov/books/NBK1130/
3. Fumagalli F, Zambon AA, Rancoita PMV, et al. Metachromatic leukodystrophy: A single-center longitudinal study of 45 patients. J Inherit Metab Dis. 2021 Sep;44(5):1151-1164. doi: 10.1002/jimd.12388
4. van Rappard DF, Boelens JJ, Wolf NI: Metachromatic leukodystrophy: Disease spectrum and approaches for treatment. Best Pract Res Clin Endocrinol Metab. 2015 Mar;29(2):261-273. doi: 10.1016/j.beem.2014.10.001
Report Available
2 to 8 daysMethod Name
Colorimetric Enzyme Assay
Forms
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing-Spanish (T826)
2. Biochemical Genetics Patient Information (T602)
3. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.
Testing Algorithm
See Lysosomal Storage Disorders Diagnostic Algorithm, Part 2