Session: SAT 41-52-HPA Axis & Disease States
Poster Board SAT-51
Method: Cortisol in the sample competes with biotinylated cortisol for binding to a monoclonal anti-cortisol-acridinium conjugate in a first incubation. Streptavidin-coupled magnetic particles are added and after further incubation and washing, the bound anti-cortisol-acridinium is measured whereby chemiluminescence generated is inversely proportional to the cortisol concentration in the sample. Total time to first result is 8 minutes. IDS-iSYS assay results were correlated against commercially available assays for serum (Roche, Cobas), urine and saliva (IBL, EIA).
Results: The assay range covering all matrices was determined at 0.05-75µg/dL with an analytical sensitivity of 0.02ug/dL. Inter-assay precision CVs were between 3.6% - 8.9% at concentrations 0.5 to 54µg/dL. For the same samples intra-assay precisions were between 2.9% - 5.9%. The assay showed linearity between 86-103% at 0.2µg/dL to 48.4µg/dL Matched serum and plasma samples were run on the IDS-iSYS showing excellent correlation (plasma = 0.92x serum + 0.95, R2=0.95, n=35). In serum samples from two external quality assessment schemes, UK NEQAS and the German DGKL, the iSYS showed excellent correlation to the Roche assay (y=0.98x + 1.69, R2=0.99, n=15; and y=0.90x + 1.86, R2=0.96, n=15). Additionally the iSYS had excellent agreement to the target gold standard mass spectrometry values of the DGKL samples (y=1.02x + 16.41, R2=0.99). Good correlation to the IBL assays was observed with urine and saliva samples (y=0.92x + 1.34, R2=0.95, n=10; and y=0.90x + 0.09, R2=0.97, n=28).
Conclusion: The data presented above demonstrate that the fully automated IDS-iSYS cortisol assay potentially presents a new, accurate and reliable immunoassay for all commonly used sample types across a wide assay range. The extremely short time to first result makes the assay suitable also for use during diagnostic procedures like adrenal vein sampling.
Disclosure: CMR: Employee, Immuno Diagnostic Systems Ltd. PG: Employee, Immuno diagnostic Systems Ltd. CR: Employee, Immuno Diagnostic Systems Ltd. ZS: Employee, Immuno Diagnostic Systems Ltd. MB: Consultant, Immunodiagnostic Systems Ltd.
*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm
See more of: Abstracts - Orals, Featured Poster Presentations, and Posters