Arylsulfatase A, 24-Hour Urine
Also known as: ARYLSULF A
Use
The Arylsulfatase A test measures the enzyme activity level in a 24-hour urine sample to evaluate patients suspected of having metachromatic leukodystrophy (MLD) or multiple sulfatase deficiency. A decreased activity level is indicative of potential MLD or sulfatase deficiencies, but may also arise in unaffected individuals with pseudoarylsulfatase A deficiency. This necessitates further confirmatory tests such as urine sulfatide analysis and molecular genetic analysis of the ARSA gene.
Special Instructions
This test requires a 24-hour urine collection. During collection, the urine should be kept refrigerated. After collection, the urine sample must be mixed well before transferring to the transport tubes. The test is not performed at ARUP laboratories, therefore, separate specimens must be submitted if multiple tests are ordered.
Limitations
The test may not detect some patients with MLD, including those with atypical forms such as those arising from Saposin B deficiency. As such, a normal result does not fully exclude all forms of MLD or multiple sulfatase deficiency. The test does not have FDA clearance or approval, thus must be interpreted within a broader clinical context and additional testing as indicated should be considered.
New York Approved
Methodology
Other
Biomarkers
Result Turnaround Time
9-19 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
6 mL
Minimum Volume
2.5 mL
Container
ARUP standard transport tubes
Collection Instructions
Collect 24-hour urine without preservatives, mix well and transfer 6 mL to transport tubes.
Storage Instructions
Refrigerate during collection.
Causes for Rejection
Random urine.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | 2 weeks |
| Frozen | Unacceptable |