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Test Code ARSU Arylsulfatase A, 24 Hour, Urine

Reporting Name

Arylsulfatase A, U

Useful For

Detection of arylsulfatase A deficiency using urine specimens

 

This test is not suitable for carrier detection.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Urine


Ordering Guidance


The preferred test to rule-out metachromatic leukodystrophy is ARSAW / Arylsulfatase A, Leukocytes.



Shipping Instructions


Specimen must be received at least 1 day prior to assay day for processing.



Necessary Information


24-Hour volume (in milliliters) is required.



Specimen Required


Supplies: Urine Tubes, 10 mL (T068)

Container/Tube: Plastic, 10-mL tube

Specimen Volume: 6 mL

Collection Instructions:

1. Collect a 24-hour urine specimen.

2. No preservative.

3. Refrigerate specimen during collection.

Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.


Specimen Minimum Volume

2.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated 14 days

Reference Values

≥19 nmol/h/mL

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

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

84311

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ARSU Arylsulfatase A, U 42726-0

 

Result ID Test Result Name Result LOINC Value
8777 Arylsulfatase A, U 42726-0
37423 Interpretation (ARSU) 59462-2
37413 Reviewed By 18771-6

Interpretation

Reduced levels of arylsulfatase A are seen in patients with metachromatic leukodystrophy (MLD).

 

Individuals with pseudodeficiency of arylsulfatase A can have results in the affected 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 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

9 to 16 days

Method 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.