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Test Code Oxysterols Oxysterols, Plasma

Useful For

Investigation of possible diagnoses of Niemann-Pick disease type C (NPC) and types A or B (NPA or NPB) in plasma specimens


Monitoring of individuals with Niemann-Pick type C disease

Seattle Children's Hospital Note:

Order: Oxysterols, Plasma

Reporting Name

Oxysterols, P

Specimen Type


Specimen Required

Collection Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Sodium heparin, lithium heparin, ACD A, or ACD B

Submission Container/Tube: Plastic vial

Specimen Volume: 0.3 mL

Seattle Children's Hospital Note:

Collect 2.0 mL whole blood

Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time
Plasma Frozen (preferred) 29 days
  Ambient  14 days
  Refrigerated  14 days

Reject Due To




Mild OK; Gross OK





Reference Values


Cutoff: ≤0.02 nmol/mL



Cutoff: ≤0.05 nmol/mL



Cutoff: ≤0.02 nmol/mL

Method Description

Plasma is added to internal standard containing d7-cholestane-3-beta, 5-alpha, 6-beta-triol (COT), and 7-ketocholesterol (7-KC). Acetonitrile (can) is then added to precipitate proteins. Following centrifugation supernatant is transferred to a 96-well plate and diluted with water. The diluted extract is subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The MS/MS is operated in multiple reaction monitoring (MRM) positive mode to follow the precursor to product species transitions for COT, 7-KC, and lyso-sphingomyelin (LSM), as well as their corresponding isotopically labeled internal standards d7-COT and d7-7-KC. The ratios of the extracted peak areas of COT, 7-KC, and LSM to their respective internal standards as determined by LC-MS/MS are used to calculate the concentration of each analyte in the sample.(Unpublished Mayo method)

Day(s) and Time(s) Performed

Tuesday, 8 a.m.

Seattle Children's Hospital Note:

TAT: 4 - 10 days

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
OXNP Oxysterols, P In Process


Result ID Test Result Name Result LOINC Value
36430 Cholestane-3beta,5alpha,6beta-triol In Process
36431 7-Ketocholesterol In Process
36432 Lyso-sphingomyelin In Process
36433 Interpretation (OXNP) 59462-2
36434 Reviewed By 18771-6

Method Name

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

Testing Algorithm

See Newborn Screen Follow-up for Niemann Pick Type A and B in Special Instructions.


For more information, see Newborn Screening Act Sheet Niemann-Pick A/B Disease: Decreased Acid Sphingomyelinase in Special Instructions.