C-reactive protein (CRP) is an acute phase reactant which is elevated in plasma in response to increased interleukin-6 induced by inflammation, infection and tissue injury. CRP is expressed mainly in the liver and activates the complement pathway following calcium-dependent binding to phosphocholine on apoptotic, necrotic and microbial cells. The sensitive quantitative measurement of total mouse CRP antigen in plasma and other biological fluids is easily performed with this 96 well strip format ELISA kit. This kit has been validated for measurement of CRP in C57 mouse plasma (20 ug/ml), Balb/C mouse plasma (3.5 ug/ml), and CD1 mouse plasma (7.2 mg/ml). The assay measures CRP antigen in the 0.02-2 ng/ml range. Samples giving mouse CRP levels above 2 ng/ml should be diluted in blocking buffer before use. For best results, dilute plasma samples 1:25,000 to 1:50,000. Mouse CRP will bind to the capture antibody coated on the microtiter plate. After appropriate washing steps, biotin labeled anti-mouse CRP primary antibody binds to the captured protein. Excess primary antibody is washed away and bound antibody is reacted with streptavidin conjugated to HRP. Following an additional washing step, TMB substrate is used for color development at 450nm. Color development is proportional to the concentration of CRP in the samples. A standard calibration curve is prepared using dilutions of purified CRP and is measured along with the test samples. All reagents and standards are provided in these ELISA kits.