Lab Dept:

Urine/Stool

Test Name:

ARYLSULFATASE A, TIMED URINE

General Information

Lab Order Codes:

UAS

Synonyms:

Arylsulfatase A, Quantitative Urine

CPT Codes:

84311 – Spectrophotometry, analyte not eslewhere specified

Test Includes:

Urine Arylsulfatase A concentration in U/L. Results from this assay may not reflect carrier status because of individual variation of arylsulfatase A enzyme levels.

Logistics

Test Indications:

Useful for detection of metachromatic leukodystrophy and as a secondary specimen for metachromatic leukodystrophy. The preferred initial specimen is leukocytes.

Lab Testing Sections:

Urine/Stool - Sendouts

Referred to:

Mayo Medical Laboratories (Test# 8777)

Phone Numbers:

Minneapolis:

Saint Paul:

612-813-6280

651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

2 – 6 days, specimens process Sunday and Wednesday, assay performed Monday and Thursday

Special Instructions:

Submit an entire 24-hour urine collection. No preservative. Refrigerate specimen during and after collection.

Note: Starting and ending times of collection are required for a timed urine collection and must be documented electronically or on the proper request form.

Specimen

Specimen Type:

Urine, timed collection

Container:

Plastic leakproof container (No preservative). Urine GUARD® collection container is preferred for a timed urine sample.

Draw Volume:

Submit an entire 24-hour urine collection

Processed Volume:

10 mL (Minimum: 5 mL) urine from a well-mixed 24 hour urine collection

Collection:

For timed urine collections, empty the bladder, discard the voided sample, and note the start time. Collect all urine voided for the specified time period. At the end of the period, note the finishing time, add the last voided sample to the container by emptying the bladder. Bring the refrigerated container to the lab. Make sure all specimens submitted to the laboratory are properly labeled with the patient’s name, medical record number and date of birth.

Special Processing:

Lab Staff: Measure total urine volume. Mix collection well before aliquot is taken. Aliquot 10 mL urine to a clean, plastic container. Record total volume and duration. Refrigerate within 4 hours of completion of 24-hour collection. Keep specimen refrigerated. Send refrigerated. Forward promptly.

Patient Preparation:

None

Sample Rejection:

Mislabeled or unlabeled specimens

Interpretive

Reference Range:

>1 U/L

Note: Results from this assay may not reflect carrier status because of individual variation of arylsulfatase A enzyme levels.

Critical Values:

N/A

Limitations:

Leukocytes are the preferred screening specimen for metachromatic leukodystrophy (MLD). Slight changes in activity occur during maturation. It is most convenient to fix the lower limit at 2.5 U/L.

Methodology:

Colorimetric, Kinetic

Contraindications:

Leukocytes are the preferred screening specimen for metachromatic leukodystrophy (MLD).

Slight changes in activity occur during maturation. It is most convenient to fix the lower limit at 2.5 U/L.

References:

Mayo Medical Laboratories Web Page May 2007