A Simple and Rapid Method Based on Liquid Chromatography-Tandem Mass Spectrometry for the Measurement of alpha-L-Iduronidase Activity in Dried Blood Spots: An Application to Mucopolysaccharidosis I (Hurler) Screening.
- Author:
Jeong Soo YANG
1
;
Hye Kyeong MIN
;
Hyeon Ju OH
;
Hye In WOO
;
Soo Youn LEE
;
Jong Won KIM
;
Junghan SONG
;
Hyung Doo PARK
Author Information
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords: Iduronidase; Mass spectrometry; Mucopolysaccharidosis I
- MeSH: *Chromatography, High Pressure Liquid; Dried Blood Spot Testing/*instrumentation; Humans; Iduronidase/*analysis/metabolism; Mucopolysaccharidosis I/blood/*diagnosis; Regression Analysis; Substrate Specificity; *Tandem Mass Spectrometry
- From:Annals of Laboratory Medicine 2015;35(1):41-49
- CountryRepublic of Korea
- Language:English
- Abstract: BACKGROUND: We developed an analytical method to measure alpha-L-iduronidase (IDUA) activity in dried blood spots. This was achieved by using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) with electrospray ionization in the positive ion mode. METHODS: Chromatographic separation was completed using mobile phase involving water-formic acid and acetonitrile-formic acid over 2.8 min of run time on a column with a Kinetex XB-C18 (Phenomenex, USA). The detection of column effluent was performed using a Xevo TQ-S triple quadrupole mass spectrometer (Waters, USA) in the multiple-reaction monitoring mode. This method was verified with blank and control samples at four activity levels: base, low, medium, and high. Control materials were provided from Centers for Disease Control and Prevention (CDC). RESULTS: Intra- and inter-day precisions were between 2.6% and 16.5% and between 7.9% and 17.0%, respectively. A correlative regression study on the IDUA activity in CDC-control samples performed to assess the validity of the developed method showed a highly significant linear association (r2=0.9976) between the calculated and CDC-reported values and an obvious difference in activity among the four levels. This reliable analytical method was applied to mucopolysaccharidosis I (Hurler) screening of patients under treatment (n=4) and in normal controls (n=129). IDUA activity ranged from 8.98 to 77.12 micromol/hr/L) in normal controls, and patients undergoing medical treatment showed low IDUA activity. CONCLUSIONS: This method had advantages of simplicity, rapid sample preparation, and liquid chromatographic separation, which efficiently inhibited ionization suppression induced by matrix effects in mass spectrometric detection.
