Analysis of acid sphingomyelinase activity in dried blood spots using tandem mass spectrometry.

Background Niemann Pick disease(NP) is a rare, lysosomal storage disorderdue to deficiency of the intra- lysosomalenzyme acid sphingomyelinase(ASM) resulting in intracellular accumulation of sphingomyelin. We evaluated a tandem mass spectrometry(MS/MS) method to analyze ASM activity in dried blood spots(DBS) that may be suitable for laboratory diagnosis of NP including high throughput screeningof at-risk populations and potentially for newborn screening.