Yi Xiao1, Xiaowei Fu2, Paul Pattengale3, Jennifer Dien Bard3, Yan-Kang Xu1, Maurice R O'Gorman4. 1. Department of Pathology and Laboratory Medicine, Children's Hospital of Los Angeles, Los Angeles, CA 90027, United States. 2. Department of Pathology and Laboratory Medicine, Children's Hospital of Los Angeles, Los Angeles, CA 90027, United States; Departments of Pathology, University of Southern California, Los Angeles, CA 90089, United States. Electronic address: xfu@chla.usc.edu. 3. Department of Pathology and Laboratory Medicine, Children's Hospital of Los Angeles, Los Angeles, CA 90027, United States; Departments of Pathology, University of Southern California, Los Angeles, CA 90089, United States. 4. Department of Pathology and Laboratory Medicine, Children's Hospital of Los Angeles, Los Angeles, CA 90027, United States; Departments of Pathology, University of Southern California, Los Angeles, CA 90089, United States; Pediatrics Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, United States. Electronic address: mogorman@chla.usc.edu.
Abstract
BACKGROUND: Oxidative stress has been implicated in numerous diseases, including arthritis, atherosclerosis, Alzheimer's disease, cancer, diabetes, hypertension, and inflammation. 8-iso-prostaglandin F2α, a member of the F2 isoprostane family, has been well-accepted as a valuable biomarker for the assessment of oxidative stress. METHODS: We report the development and validation of an ultra-sensitive LC-MS/MS assay for urinary 8-iso-PGF2α measurements in pediatric population. RESULTS: The assay was linear from 0.024 to 20nmol/l (R(2)=0.99). Recoveries were above 85% and matrix effects were below 5%. The variability was determined at nmol/l concentration: the intra-day variability (%CV) ranged from 3.9% to 4.5% (n=20); and the inter-day variability ranged from 4.3% to 5.7% (n=20). The accuracy of our laboratory developed test was evaluated with a clinical reference laboratory (n=39), and a correlation coefficient of 0.9257 was observed. Reference interval were established to be <0.5ng/mg creatinine in a group of pediatric population (2months-18years, n=123). CONCLUSIONS: The precision of the assay will allow for accurate assessment of oxidative stress, and is acceptable for patient testing, particularly in pediatric population.
BACKGROUND: Oxidative stress has been implicated in numerous diseases, including arthritis, atherosclerosis, Alzheimer's disease, cancer, diabetes, hypertension, and inflammation. 8-iso-prostaglandin F2α, a member of the F2 isoprostane family, has been well-accepted as a valuable biomarker for the assessment of oxidative stress. METHODS: We report the development and validation of an ultra-sensitive LC-MS/MS assay for urinary 8-iso-PGF2α measurements in pediatric population. RESULTS: The assay was linear from 0.024 to 20nmol/l (R(2)=0.99). Recoveries were above 85% and matrix effects were below 5%. The variability was determined at nmol/l concentration: the intra-day variability (%CV) ranged from 3.9% to 4.5% (n=20); and the inter-day variability ranged from 4.3% to 5.7% (n=20). The accuracy of our laboratory developed test was evaluated with a clinical reference laboratory (n=39), and a correlation coefficient of 0.9257 was observed. Reference interval were established to be <0.5ng/mg creatinine in a group of pediatric population (2months-18years, n=123). CONCLUSIONS: The precision of the assay will allow for accurate assessment of oxidative stress, and is acceptable for patient testing, particularly in pediatric population.