Variability among TSH Measurements Can Be Reduced by Combining a Glycoengineered Calibrator to Epitope-Defined Immunoassays.

Objectives: Measuring protein markers with variable glycosylation, such as thyroid-stimulating hormone (TSH), with high accuracy is not an easy task. Despite highly sensitive third-generation tests, discrepancies among TSH assays still remain unsolved and are the focus of important standardization efforts. Earlier work from our group showed that a lack of similarity in epitope expression between standards and samples may account for discordant hormone measurements.