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HelpTest Code ARSU Arylsulfatase A, 24 Hour, Urine
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
Arylsulfatase A, USpecimen Type
UrineOrdering 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.
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated | 14 days |
Specimen Minimum Volume
2.5 mL
Special Instructions
Day(s) Performed
Tuesday
Specimen Retention Time
1 monthReport Available
9 to 16 daysReference 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.
Useful For
Detection of arylsulfatase A deficiency using urine specimens
This test is not suitable for carrier detection.
Testing Algorithm
See Lysosomal Storage Disorders Diagnostic Algorithm, Part 2
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 |
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.
Genetics Test Information
Metachromatic leukodystrophy (MLD) is caused by deficient activity of arylsulfatase A (ARSA) enzyme and is characterized by progressive neurologic changes and leukodystrophy with variable age of onset.
Pseudodeficiency of arylsulfatase A (ARSA) enzyme has been recognized with increasing frequency among patients with other apparently unrelated neurologic conditions as well as among the general population.
This test is not suitable for carrier detection.
Leukocytes are the preferred screening specimen for metachromatic leukodystrophy.
Additional studies, such as molecular genetic testing of ARSA (CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies; specify ARSA Gene List ID: IEMCP-WHFH2K ), urinary excretion of sulfatides (CTSA / Ceramide Trihexosides and Sulfatides, Urine), and histological analysis for metachromatic lipid deposits in nervous system tissue are recommended to confirm a diagnosis.