Acid Sphingomyelinase, Leukocytes
Use
The test is useful for investigating the possible diagnosis of Niemann-Pick disease types A and B. It is particularly applicable for diagnostic testing in patients with decreased acid sphingomyelinase activity detected on newborn screening or clinical signs and symptoms suspicious for Niemann-Pick type A or B. Niemann-Pick disease types A and B result from a deficiency in the enzyme sphingomyelinase, causing storage issues with sphingomyelin and cholesterol in several organs. Accurate diagnosis can guide further biochemical testing and molecular genetic assessments.
Special Instructions
Specimens for this test should arrive refrigerated within 6 days of collection to ensure proper isolation of leukocytes. Collect specimens Monday through Thursday, avoiding collection on the day prior to a holiday. Specimens should be collected and packaged near the time of shipping to the lab. New York clients must include informed consent documentation with the test order.
Limitations
The test is not recommended for carrier detection due to a wide range of enzymatic activities in both carriers and noncarriers. False-positive results can occur, necessitating additional biochemical or molecular testing to confirm a diagnosis if enzyme deficiencies are detected. Abnormal results require a detailed interpretation, potentially followed by further confirmatory studies.
New York Approved
Methodology
Mass Spectrometry (Other)
Biomarkers
LOINC Codes
- 24101-8
- 24101-8
- 59462-2
- 18771-6
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 preferred; acceptable: Yellow top (ACD solution A) or lavender top (EDTA))
Collection Instructions
Send specimen in original tube. Do not aliquot.
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 6 days |
| Refrigerated | 6 days |