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Test Code Niem Pk C Niemann-Pick Type C Detection, Fibroblasts

Reporting Name

Niemann-Pick Type C, Fibro

Useful For

Diagnosis of Niemann-Pick disease type C


Specimen Required


Submit only 1 of the following specimens:

 

Specimen Type: Cultured fibroblasts

Container/Tube: T-75 or T-25 flask

Specimen Volume: 1 Full T-75 flask or 2 full T-25 flasks

Specimen Stability Information: Ambient (preferred)/Refrigerated <24 hours

 

Specimen Type: Skin biopsy

Supplies: Fibroblast Biopsy Transport Media (T115)

Container/Tube: Sterile container with any standard cell culture media (eg, minimal essential media, RPMI 1640). The solution should be supplemented with 1% penicillin and streptomycin. Tubes can be supplied upon request (Eagle's minimum essential medium with 1% penicillin and streptomycin [T115]).

Specimen Volume: 4-mm punch

Specimen Stability Information: Refrigerated (preferred)/Ambient


Specimen Type

Tissue

Specimen Stability Information

Specimen Type Temperature Time
Tissue Varies

Day(s) and Time(s) Performed

Varies

Performing Laboratory

Mayo Medical Laboratories in Rochester

Method Name

NIEM: Radiolabeled Lipid Extraction Using Thin Layer Chromatography

CRYOB: Fibroblast Subculture Followed by Cryopreservation and Storage

Method Description

The formation of (3)H-cholesterol oleate is measured against cells that are fed only (3)H-oleic acid without low-density lipoprotein. The formed (3)H-cholesterol oleate is separated from (3)H-oleic acid and its other esterified forms by thin-layer chromatography (TLC). The areas on the TLC plates corresponding to the cholesterol oleate markers are then scraped and counted on a liquid scintillation counter. Lowry proteins are done on the cell pellet to normalize the assay roughly to cell numbers. Filipin staining for cholesterol is performed on all specimens with low values.(Kruth HS, Comly ME, Butler JD, et al: Type C Niemann-Pick disease: abnormal metabolism of low density lipoprotein in homozygous and heterozygous fibroblasts. J Biol Chem 1986;261:16769-16774; Pentchev PG, Kruth HS, Comley ME, et al: Type C Niemann-Pick disease: a parallel loss of regulatory responses in both the uptake and esterification of low density lipoprotein-derived cholesterol in cultured fibroblasts. J Biol Chem 1986;261:16775-16780)

Reference Values

If the results indicate that the patient's cultured fibroblasts esterify cholesterol at a level that is <10% of normal cultured fibroblasts and when filipin staining shows excessive storage of free cholesterol, it will be stated that the patient is positive for Niemann-Pick type C disease. All samples will be stained by filipin to see if a milder biochemical phenotype is the likely cause of the Niemann-Pick disease-like clinical picture.

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

82658-Niemann-Pick type C detection

88233-Fibroblast culture

88240-Cryopreservation for biochemical studies

LOINC Code Information

Test ID Test Order Name Order LOINC Value
NIEM Niemann-Pick Type C, Fibro In Process

 

Result ID Test Result Name Result LOINC Value
30173 Cholesterol Esterification In Process
29746 Interpretation (NIEM) 59462-2
29748 Reviewed By No LOINC Needed

Testing Algorithm

When this test is ordered, a fibroblast culture and cryopreservation for biochemical studies will always be performed at an additional charge. However, for multiple lysosomal enzyme assays on a patient utilizing fibroblast culture, only 1 culture is required regardless of the number of enzyme assays ordered. If viable cells are not obtained within 10 days, client will be notified.

Reject Due To

Hemolysis

NA

Lipemia

NA

Icterus

NA

Other

Specimen in formalin or fixative preservative

Additional Tests

Test ID Reporting Name Available Separately Always Performed
FIBR Fibroblast Culture Yes Yes
CRYOB Cryopreserve for Biochem Studies No Yes

Forms

1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.

2. Biochemical Genetics Patient Information (T602) in Special Instructions