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HelpOrder Code OXYWB Oxysterols, Blood
Ordering Guidance
Based on internal validation studies, this test using dried blood spots created from a whole blood specimen is less clinically sensitive and specific for diagnosing Niemann-Pick type C (NPC) (75% and 89%, respectively) than using plasma (98%). If there is a strong clinical suspicion for NPC, order OXNP / Oxysterols, Plasma.
This test is also available as a part of a panel, see HSMWB / Hepatosplenomegaly Panel, Blood. If this test (OXYWB) is ordered with either GPSYW / Glucopsychosine, Blood or CTXWB / Cerebrotendinous Xanthomatosis, Blood, the individual tests will be canceled and HSMWB ordered.
Specimen Required
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Green top (sodium heparin, lithium heparin) or yellow top (ACD B)
Specimen Volume: 1 mL
Collection Instructions: Send whole blood specimen in original tube. Do not aliquot.
Forms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.
Useful For
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
This test is not recommended for diagnosis of Niemann-Pick type C (NPC). If NPC is suspected, consider plasma oxysterols.
This test is not useful for the identification of carriers
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Oxysterols, BSpecimen Type
Whole bloodSpecimen Minimum Volume
0.25 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole blood | Refrigerated (preferred) | 72 hours |
| Ambient | 48 hours |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
Cholestane-3-beta,5-alpha,6-beta-triol
Cutoff: ≤0.800 nmol/mL
Lyso-sphingomyelin
Cutoff: ≤0.100 nmol/mL
Method Description
Whole blood is spotted onto filter paper and dried overnight. A 3-mm dried blood spot is extracted with internal standard. The extract is subjected to liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. The MS/MS is operated in the multiple reaction monitoring positive mode to follow the precursor to product species transitions for each analyte and internal standard. The ratio of the extracted peak areas to internal standard determined by the LC-MS/MS is used to calculate the concentration of in the sample.(Unpublished Mayo method)
Day(s) Performed
Tuesday, Thursday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
82542
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| OXYWB | Oxysterols, B | 92738-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| BA4354 | Interpretation (OXYWB) | 59462-2 |
| BA4352 | Cholestane-3beta,5alpha,6beta-triol | 92756-6 |
| BA4353 | Lyso-sphingomyelin | 92748-3 |
| BA4355 | Reviewed By | 18771-6 |
Testing Algorithm
If the patient has abnormal newborn screening results for acid sphingomyelinase deficiency, also called Niemann-Pick type A or B disease, refer to the appropriate American College of Medical Genetics and Genomics Newborn Screening ACT Sheet.(1)