Abstract: The present invention provides a method for performing a localised RCA reaction comprising at least two rounds of RCA, wherein the product of a second RCA reaction is attached, and hence localised, to a product of a first RCA reaction, said method comprising: (a) providing a first RCA product; (b) directly or indirectly hybridising to said first RCA product a probe which comprises or provides a primer for a second RCA reaction; and (c) performing a second RCA reaction using said RCA primer of (b) to form a second RCA product, wherein in said reaction: (i) said probe and said primer are not able to prime extension using said first RCA product as template or any such extension is limited to avoid displacement of any probe hybridised to the first RCA product; (ii) the direct or indirect hybridisation of the RCA primer of (b) to the first RCA product is maintained and, by virtue of said hybridisation, the second RCA product is attached to the first RCA product; (iii) a RCA template for said second RCA reaction is

Abstract: The present invention relates to a proximity-probe based detection assay for detecting an analyte in a sample and in particular to a method that comprises the use of at least one set of at least first and second proximity probes, which probes each comprise an analyte-binding domain and a nucleic acid domain and can simultaneously bind to the analyte directly or indirectly, wherein the nucleic acid domain of at least one of said proximity probes comprises a hairpin structure that can be unfolded by cleavage of the nucleic acid domain to generate at least one ligatable free end or region of complementarity to another nucleic acid molecule in said sample, wherein when the probes bind to said analyte unfolding said hairpin structure allows the nucleic acid domains of said at least first and second proximity probes to interact directly or indirectly.