Diagnosis; Monitoring

Establish or confirm diagnosis

Investigation of possible diagnoses of Niemann-Pick disease types A or B in blood spot specimens. This test is not suitable for the identification of carriers.

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peak areas to internal standard is determined by LC-MS/MS is used to calculate the concentration of in the sample.(Unpublished Mayo method) View more

Tests performed
Entire test performed in-house

Recovery was used to assess accuracy; mean recovery was 100%. Intra assay precision was performed at 2 levels: CV results ranged from 10% to 21% (N=20 each). Inter assay precision was performed at 2 levels: CV results ranged from 20% to 25% (N=20 each). The analytical measurement range is analyte … Recovery was used to assess accuracy; mean recovery was 100%. Intra assay precision was performed at 2 levels: CV results ranged from 10% to 21% (N=20 each). Inter assay precision was performed at 2 levels: CV results ranged from 20% to 25% (N=20 each). The analytical measurement range is analyte dependent and ranges from 0.016-1.75 nmol/mL. View more

Nonspecific neonatal cholestasis may result in elevations of cholestane-3-beta, 5-alpha, 6-beta-triol (COT) and lyso-sphingomyelin 509 (LSM 509). This test may pick up cases of Niemann-Pick type C, however a normal result in dried blood spots does not rule it out.

Is proficiency testing performed for this test? Help
Yes

Method used for proficiency testing: Help
Intra-Laboratory

Description of PT method: Help
Intra-laboratory alternative assessment of performance through quality control or patient blind testing

Description of internal test validation method: Help
This test was laboratory developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements.