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Order Code OXYWB Oxysterols, Blood


Ordering Guidance


This test's clinical sensitivity and specificity for the identification of Niemann-Pick type C (NPC) is 75% and 89%, respectively. If NPC is strongly suspected, the recommended test is 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 vial. Do not aliquot.


Useful For

Investigating a possible diagnosis of Niemann-Pick disease type A, B, or C using whole blood specimens

 

Monitoring of individuals with Niemann-Pick type C disease

 

This test is not useful for the identification of carriers.

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Reporting Name

Oxysterols, B

Specimen Type

Whole blood

Specimen 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peak areas to internal standard determined by the LC-MS/MS is used to calculate the concentration of in the sample.(Unpublished Mayo method)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

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

82542

Testing Algorithm

If the patient has abnormal newborn screening results for Niemann- Pick disease, refer to the appropriate American College of Medical Genetics and Genomics Newborn Screening ACT Sheet.(1)