Clinical Microbiology: Open Access

Cross-reactivity of synthetic corticosteroids on cortisol serum levels: A comparison between three different immunoassays

4^th International Conference on Clinical Microbiology and Microbial Genomics

October 05-07, 2015 Philadelphia, USA

Yannick Wouters

Katholieke Universiteit Leuven, Belgium

Posters-Accepted Abstracts: Clin Microbiol

Abstract:

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 methylprednisolone 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 5μg/dl and a higher concentration in normal range of 15μg/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.

Biography :

Email: Yannick_wouters@outlook.be