Oxysterols, Blood
Use
Investigating a possible diagnosis of acid sphingomyelinase deficiency, also known as Niemann-Pick disease type A or B, using dried blood spots created from a whole blood specimen. The test aids in identifying Niemann-Pick disease type A and B due to mutations in the SMPD1 gene causing sphingomyelin and cholesterol storage in tissues like the liver and spleen. Diagnosis of NPC is not recommended with this test; plasma oxysterols are preferred for NPC suspicion.
Special Instructions
This test should be ordered with caution as it may be less clinically sensitive and specific for diagnosing Niemann-Pick type C (NPC) than using plasma. If ordered with GPSYW or CTXWB, the individual tests will be canceled and the panel HSMWB will be ordered.
Limitations
The test is less clinically sensitive and specific for diagnosing Niemann-Pick type C (NPC) with only 75% sensitivity and 89% specificity compared to plasma's 98% sensitivity. It is not useful for identifying carriers of Niemann-Pick disease type A or B. Improper specimen collection and processing, such as using aliquoted samples or non-EDTA tubes, may impact the results.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 92738-4
- 59462-2
- 92756-6
- 92748-3
- 18771-6
Result Turnaround Time
3-7 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
1 mL
Minimum Volume
0.25 mL
Container
Lavender top (EDTA); Green top (sodium heparin, lithium heparin) or yellow top (ACD B) acceptable.
Collection Instructions
Send whole blood specimen in original tube. Do not aliquot.
Causes for Rejection
Gross hemolysis, lipemia, icterus.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 48 hours |
| Refrigerated | 72 hours |