Katholieke Universiteit Leuven, Belgium
Posters-Accepted Abstracts: J Drug Metab Toxicol
Immunoassays are widely used in clinical laboratories as they have high specificity and are easy in use. A downside of these assays is cross-reactivity with structurally similar molecules to the analyte, which could lead to false clinical interpretation. Due to structural similarity between methyl prednisolone and prednisolone and the analyte, falsely elevated cortisol levels have been reported with cortisol immunoassays. This study made a comparison between a manual radio immunoassay (RIA) and two automated cortisol assays on Cobas�?® 8000 (Cortisol I) and Modular�?® E170 (Cortisol II). Patientâ�?�?s serum samples were pooled to obtain two concentration levels: A lower cortisol concentration of 5�?¼g/dl and a higher concentration in normal range of 15�?¼g/dl. Serum samples were spiked with different concentrations of prednisolone and methylprednisolone corresponding to commonly used oral doses of synthetic corticosteroid, ranging from 1 mg to 1000 mg (2000 mg) prednisolone (methylprednisolone), as found in literature. Serum was also spiked with a single concentration of dexamethasone, corresponding to a supra-therapeutic dosage of 800 mg per OS, which was expected to have no cross-reactivity with either assay. In one volunteer, serum cortisol levels were measured at different time intervals after the intake of 32 mg Medrol�?®, the next day after a late-night intake of 2 mg dexamethasone. Differences in elevated cortisol levels by each assay could be indicative for the interference of in vivo metabolites of methylprednisolone.
Yannick Wouters started at the University of Antwerp studying Biochemical Sciences, which he later on extended with a degree in drug development (Pharmacist). As of his great interest in biochemical markers he was given the opportunity to start a 5 year medical residency at the Catholic University of Leuven for the recognition as Clinical Biologist. In his current position he works as an Intern in Microbiology at the clinical laboratory in H-Hartziekenhuis Lier. He is also active as a Board Member of Farmant VZW, which organizes study courses for pharmacists in the field.