BACKGROUND: Fluorometric and tandem mass spectrometry assays can be used to measure lysosomal enzyme activities in dried blood spots (DBS). The effect of DBS preparation, storage and shipping was evaluated on the activities of acid α-glucosidase, acid α-galactosidase, acid β-glucocerebrosidase, acid sphingomyelinase, and galactocerebrosidase. METHODS: Whole blood from normal donors was used to prepare DBS following Clinical and Laboratory Standards Institute guidelines and by several deviations. Some DBS were subjected to various treatments, storage and shipping conditions. The activity of 5 lysosomal enzymes (GAA, GLA, GBA, ASM, and GALC) was measured using tandem mass spectrometric and fluorometric (GAA only) assays with 2 distinct and commonly used synthetic substrates. RESULTS: Enzyme activities were strongly affected by the way DBS were prepared and stored. Exposure of DBS to elevated heat and humidity can destroy enzyme functions rapidly. DBS prepared from poorly mixed blood caused significant variation on enzyme activities. EDTA, but not heparin, as an anti-coagulant gave more precise results. CONCLUSIONS: The study confirmed the importance of proper and consistent DBS preparation and storage when screening for deficiencies of lysosomal enzymes.
BACKGROUND: Fluorometric and tandem mass spectrometry assays can be used to measure lysosomal enzyme activities in dried blood spots (DBS). The effect of DBS preparation, storage and shipping was evaluated on the activities of acid α-glucosidase, acid α-galactosidase, acid β-glucocerebrosidase, acid sphingomyelinase, and galactocerebrosidase. METHODS: Whole blood from normal donors was used to prepare DBS following Clinical and Laboratory Standards Institute guidelines and by several deviations. Some DBS were subjected to various treatments, storage and shipping conditions. The activity of 5 lysosomal enzymes (GAA, GLA, GBA, ASM, and GALC) was measured using tandem mass spectrometric and fluorometric (GAA only) assays with 2 distinct and commonly used synthetic substrates. RESULTS: Enzyme activities were strongly affected by the way DBS were prepared and stored. Exposure of DBS to elevated heat and humidity can destroy enzyme functions rapidly. DBS prepared from poorly mixed blood caused significant variation on enzyme activities. EDTA, but not heparin, as an anti-coagulant gave more precise results. CONCLUSIONS: The study confirmed the importance of proper and consistent DBS preparation and storage when screening for deficiencies of lysosomal enzymes.
Authors: Yang Liu; Fan Yi; Arun Babu Kumar; Naveen Kumar Chennamaneni; Xinying Hong; C Ronald Scott; Michael H Gelb; Frantisek Turecek Journal: Clin Chem Date: 2017-04-20 Impact factor: 8.327
Authors: Pavlina Wolf; Roy N Alcalay; Christopher Liong; Emmaline Cullen; Michael W Pauciulo; William C Nichols; Ziv Gan-Or; Wendy K Chung; Tina Faulkner; Christopher Bentis; Robert J Pomponio; Xiwen Ma; X Kate Zhang; Joan M Keutzer; Petra Oliva Journal: Mol Genet Metab Date: 2017-10-23 Impact factor: 4.797
Authors: Mariana Barcenas; Chang Xue; Tatyana Marushchak-Vlaskin; C Ronald Scott; Michael H Gelb; František Tureček Journal: Anal Chem Date: 2014-07-21 Impact factor: 6.986