Abstract: Compositions, methods, and kits comprising calibrators with enhanced stability for immunoassays are provided. The compositions and kits of the invention comprise calibrators that have been linearized. They include calibrators that have been exposed, in a denatured state, to at least one ionic surface charge modifier, and they include calibrators that have been denatured in the presence of an ionic surface charge modifier. Ionic surface charge modifiers include, for example, sodium dodecyl sulfate. Methods for preparing calibrator preparations of enhanced stability, including methods that comprise exposing a calibrator preparation to an ionic surface charge modifier while the calibrator is in a denatured state, are provided. The compositions and kits include calibrators that are protein/polypeptide antigens and non-protein/polypeptide antigens and haptens. The compositions and kits include calibrator media for immunoassays prepared in accordance with the invention.