Specific binding assays

A method of detecting the presence of an analyte of interest in a sample, the method comprising the steps of:

• providing a solid support comprising an analogue of the analyte of interest, said solid support further comprising a binding partner reversibly immobilised thereon by interaction with said analogue, the binding partner having lower binding affinity for the analogue than for the analyte of interest;
• specifically displacing the bin din g partner from the solid support in response to the presence of the analyte of interest in the sample, said displacement causing a reduction in the mass of material immobilised on the solid support, thereby generating a detect able change in a mass-dependent property of the solid support;
• and
• detecting the presence of said analyte of interest by detecting said change.