Patent ID: 8153436
Filing Date: 2012-04-10
Classification: G01N

Abstract:
1. A method of assaying for crystallized calcium pyrophosphate dihydrate (CPPD) in a biological sample, comprising: (i) contacting a biological sample from a patient with an excess of a detectable calcium crystal-tagging compound reactive with a plurality of crystallized calcium species under conditions that allow the detectable calcium crystal-tagging compound to react with any crystallized calcium species present in the biological sample to form detectable crystallized calcium complexes, wherein the detectable calcium crystal-tagging compound is radiolabeled phosphocitrate; (ii) removing substantially all unreacted detectable calcium crystal-tagging compound; (iii) contacting the detectable crystallized calcium complexes with a reagent that selectively degrades CPPD to release a soluble detectable species, wherein (x) the reagent that selectively degrades CPPD is a pyrophosphorylase or pyrophosphatase and (y) the soluble detectable species is dissolved mineral containing the radiolabel; and (iv) detecting the soluble detectable species, thereby detecting the presence of CPPD in the biological sample.