Abstract:

Objective To establish a method for the determination of the activities of acid-beta-glucocerebrosidase （ABG）and acid sphingomyelinase （ASM） in dried blood spot specimens by ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）. Methods The extraction of dried blood spot specimens was incubated with enzyme substrates and internal standards overnight,and the reaction solution was extracted,dried under nitrogen and reconstituted. The concentrations and internal standards were analyzed by UPLC-MS/MS,and the activities of enzymes were calculated. Linearity,precision and accuracy were analyzed. Results The within-run and between-run precisions for ABG and ASM activities were 3.6%-8.4%,and the within-run and between-run accuracies were 101%-115%. ABG and ASM activities of healthy newborns showed a skewed distribution（P<0.01）. The reference intervals for ABG and ASM activities were 5.52-49.50 and 2.02-15.44 μmol·L^-1·h^-1 according to 0.5th-99.5th percentiles. After judgement,the determination rate for Gaucher disease（GD）or Niemann-Pick disease type A/B （NPA/B）patient was 100%. Conclusions UPLC-MS/MS can determine ABG and ASM activities in dried blood spot specimens simultaneously,and it is rapid and specific,which could be applied in newborn screening of high-throughput determinations for GD and NPA/B.

Key words: Acid-beta-glucocerebrosidase, Acid sphingomyelinase, Tandem mass spectrometry, Dried blood spot