The Quantikine Human IL-1 beta Immunoassay is a 3.5 or 4.5 hour solid phase ELISA designed to measure IL-1 beta in cell culture supernates, serum, and plasma. It contains E. coli-expressed recombinant human IL-1 beta and antibodies raised against the recombinant factor. It has been shown to quantitate recombinant human IL-1 beta accurately. Results obtained using natural IL-1 beta showed linear curves that were parallel to the standard curves obtained using the Quantikine kit standards. These results indicate that this kit can be used to determine relative mass values for natural IL-1 beta. Reports indicate that this and other ELISA kits calibrated using mature IL-1 beta as a standard will detect, but considerably underestimate, the unprocessed IL-1 beta precursor present in samples. In biological samples other than cell lysates, the precursor form of IL-1 beta is usually not the predominant form of IL-1 beta present and, additionally, is not biologically active. Therefore, results obtained using this kit should provide a useful measure of the levels of active IL-1 beta present in biological fluids. Range: 3.90 - 250 pg/mL. Sensitivity: 1 pg/mL. Time: 3.5 hours or 4.5 hours