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Test ID OXYBS Oxysterols, Blood Spot

Useful For

Investigation of possible diagnosis of Niemann-Pick disease types A, B, or C in blood spot specimens


Monitoring of individuals with Niemann-Pick disease type C


This test is not suitable for the identification of carriers.

Method Name

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

Reporting Name

Oxysterols, BS

Specimen Type

Whole 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 available separately as well as a part of HSMBS / Hepatosplenomegaly Panel, Blood Spot. If this test is ordered with either GPSY / Glucopsychosine, Blood Spot or CTXBS / Cerebrotendinous Xanthomatosis, Blood Spot, the individual tests will be canceled and HSMBS ordered.

Specimen Required


-Card-Blood Spot Collection (Filter Paper) (T493)

-Card-Postmortem Screening (Filter Paper) (T525)


Preferred: Blood Spot Collection (Filter Paper)

Acceptable: Whatman Protein Saver 903 filter paper, PerkinElmer 226 (formerly Ahlstrom 226) filter paper, Munktell filter paper, Postmortem Screening Card or collected with EDTA, sodium heparin, lithium heparin, or ACD B-containing devices

Specimen Volume: 2 Blood spots

Collection Instructions:

1. Let blood dry completely on the filter paper at ambient temperature in a horizontal position for a minimum of 3 hours.

2. At least 1 spot should be complete, (ie, unpunched).

3. Do not expose specimen to heat or direct sunlight.

4. Do not stack wet specimens.

5. Keep specimen dry.

Additional Information:

1. For collection instructions, see Blood Spot Collection Instructions.

2. For collection instructions in Spanish, see Blood Spot Collection Card-Spanish Instructions (T777).

3. For collection instructions in Chinese, see Blood Spot Collection Card-Chinese Instructions (T800).

Specimen Minimum Volume

1 Blood spot

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole blood Refrigerated (preferred) 10 days FILTER PAPER
  Frozen  59 days FILTER PAPER
  Ambient  10 days FILTER PAPER

Clinical Information

Niemann-Pick disease types A, B, and C (NPA, NPB, and NPC, respectively) are a group of autosomal recessive lysosomal storage disorders affecting metabolism of specific lipids within cells.


NPA and NPB are caused by a deficiency of sphingomyelinase that results in extensive storage of sphingomyelin and cholesterol in the liver, spleen, lungs, and, to a lesser degree, brain. NPA disease is more severe than NPB and is characterized by early onset with feeding problems, dystrophy, persistent jaundice, development of hepatosplenomegaly, neurological deterioration, deafness, and blindness leading to death by age 3 years of age. NPB disease is limited to visceral symptoms with survival into adulthood. Some patients have been described with intermediary phenotypes. Characteristic of the disease are large lipid-laden foam cells. Approximately 50% of cases have cherry-red spots in the macula. Sphingomyelinase is encoded by the SMPD1 gene.


The combined prevalence of NPA and NPB is estimated to be 1 in 250,000. NPA and NPB are inherited in an autosomal recessive manner and are caused by variants in the SMPD1 gene. Although there is a higher frequency of type A among the Ashkenazi Jewish population, both types are panethnic. Individuals with NPA and NPB typically have elevations of lyso-sphingomyelin (LSM) and lyso-sphingomyelin 509 (LSM 509) combined with potential elevations in cholestane-3 beta, 5 alpha, 6 beta-triol (COT) or 7-ketocholesterol (7-KC). Molecular genetic testing for NPA and NPB disease is also available (see CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies; specify gene list ID: IEMCP-W6S9XD).


NPC is caused by a defect in cellular cholesterol trafficking that results in the progressive accumulation of unesterified cholesterol in late endosomes/lysosomes.(1) NPC is considered a lipid storage disorder with variable age of onset (range: perinatal period to adulthood), and highly variable clinical presentation. Most individuals are diagnosed during childhood with symptoms that include ataxia, vertical supranuclear gaze palsy, dystonia, progressive speech deterioration, and seizures. Infants may present with or without hepatosplenomegaly and respiratory failure. Those without liver and pulmonary disease may present with hypotonia and developmental delay. Adult-onset NPC is associated with a slower progression and is characterized by psychiatric illness, ataxia, dystonia, and speech difficulties.


The incidence of NPC is approximately 1 in 120,000 to 150,000 live births. NPC is an autosomal recessive condition and is caused by variants in either the NPC1 or NPC2 genes. Most individuals with NPC exhibit elevated levels of oxysterol COT in dried blood spots, however, testing in plasma (OXNP / Oxysterols, Plasma) is more sensitive, particularly in patients with an atypical presentation. Elevations may also be seen in lyso-sphingomyelin 509 (LSM 509) and 7-KC. The diagnosis of NPC can be confirmed by demonstration of impaired cholesterol esterification and positive filipin staining in cultured fibroblasts (NIEM / Niemann-Pick Type C Detection, Fibroblasts) or by molecular genetic analysis of the NPC1 and NPC2 genes (see CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies; specify gene list ID: IEMCP-H683JG).

Reference Values


Cutoff: ≤0.800 nmol/mL



Cutoff: ≤0.100 nmol/mL


An elevation of cholestane-3-beta, 5-alpha, 6-beta-triol is highly suggestive of Niemann-Pick disease type C (NPC) disease.


An elevation of lyso-sphingomyelin is highly suggestive of Niemann-Pick disease type A or B (NPA or NPB) disease.


An elevation of lyso-sphingomyelin 509 is suggestive of NPA, NPB or NPC disease.

Clinical Reference

1. OMIM: 257220 Niemann-Pick Disease, Type C1; NPC1. Updated May 26, 2020. Accessed February 3, 2021. Available at

2. OMIM: 257200 Niemann-Pick Disease Type A. Updated October 19, 2016. Accessed February 3, 2021. Available at

3. OMIM: 607616 Niemann-Pick Disease Type B. Updated April 4, 2019. Accessed February 3, 2021. Available at

4. Wasserstein MP, Schuchman EH: Acid sphingomyelinase deficiency. In: Adam MP, Ardinger HH, Pagon RA, et al, eds. GeneReviews [Internet]. University of Washington, Seattle; 2006. Updated June 18, 2015. Accessed November 2, 2020. Available at

5. Patterson MC, Vanier MT, Suzuki K, et al: Niemann-Pick disease type C: a lipid trafficking disorder. In: Valle D, Antonarakis S, Ballabio A, Beaudet AL, Mitchell GA, eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill; 2019. Accessed November 2, 2020. Available at

6. Gal AE, Brady RO, Hibbert SR, Pentchev PG: A practical chromogenic procedure for the detection of homozygotes and heterozygous carriers of Niemann-Pick disease. N Engl J Med. 1975 Sep 25;293(13):632-636

7. Patterson M: Niemann-Pick disease type C. In: Adam MP, Ardinger HH, Pagon RA, et al, eds. GeneReviews [Internet]. University of Washington, Seattle; 2000. Updated December 10, 2020. Accessed February 3, 2021. Available at

8. Schuchman EH: The pathogenesis and treatment of acid sphingomyelinase-deficient Niemann-Pick disease. Int J Clin Pharmacol Ther. 2009;47(Suppl 1):S48-S57

9. Hollack CEM, de Sonnaville ESV, Cassiman D et al: Acid sphingomyelinase (Asm) deficiency patients in The Netherlands and Belgium: disease spectrum and natural course in attenuated patients. Mol Genet Metab. 2012 Nov;107(3):526-533

10. Geberhiwot T, Moro A, Dardis A, et al; International Niemann-Pick Disease Registry (INPDR): Consensus clinical management guidelines for Niemann-Pick disease type C. Orphanet J Rare Dis. 2018 Apr 6;13(1):50

Day(s) Performed


Report Available

2 to 9 days

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 US Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
OXYBS Oxysterols, BS 92741-8


Result ID Test Result Name Result LOINC Value
36762 Interpretation (OXYBS) 59462-2
36760 Cholestane-3beta,5alpha,6beta-triol 92757-4
36761 Lyso-sphingomyelin 92749-1
36763 Reviewed By 18771-6
Mayo Clinic Laboratories | Pediatric Catalog Additional Information: