A catalytic conformational sensor method for detecting abnormal proteins and proteinaceous particles. The method is based on the interaction of a peptide fragment or probe with an abnormal proteinaceous particle. The interaction catalyzes transformation of the probe to a predominately beta sheet conformation and allows the probe to bind to the abnormal proteinaceous particle. This in turn, catalyzes propagation of a signal associated with the test sample-bound probe. As a result signals can be propagated even from samples containing very low concentrations of abnormal proteinaceous particles as is the case in many body-fluid derived samples.