Alpha-L-Iduronidase, Leukocytes
Use
This test is useful for diagnosing mucopolysaccharidosis I, including Hurler, Scheie, and Hurler-Scheie syndromes in leukocytes. It provides diagnostic testing for patients with clinical signs and symptoms suspicious for mucopolysaccharidosis type I (MPS I). Enzyme testing is included in the diagnostic workup for infants following a positive newborn screen result for MPS I. The test measures the activity of alpha-L-iduronidase enzyme to confirm a diagnosis of MPS I, as deficiency can lead to a wide range of symptoms due to glycosaminoglycan accumulation.
Special Instructions
Not provided.
Limitations
The presence of a pseudodeficiency allele may cause reduced activity of alpha-L-iduronidase in the artificial substrate, resulting in values below the normal reference range but higher than typical for MPS I patients. This test does not differentiate between Hurler and Scheie syndromes. Enzyme levels may appear normal in individuals receiving enzyme replacement therapy or who have undergone hematopoietic stem cell transplant. Enzymatic testing is not reliable for carrier detection.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
Alpha-L-iduronidase
Other
LOINC Codes
- 24057-2 - A-L-Iduronidase WBC-cCnt
- 24057-2 - A-L-Iduronidase WBC-cCnt
- 59462-2 - Clinical biochemist review
- 18771-6 - Provider signing name
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
6 mL
Minimum Volume
4 mL
Container
Yellow top (ACD solution B)
Collection Instructions
Send whole blood specimen in original tube. Do not aliquot.
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 6 days |
| Refrigerated | 6 days |