The Quantikine Human GM-CSF Immunoassay is a 3.5 or 4.5 hour solid phase ELISA designed to measure GM-CSF levels in cell culture supernates, serum, and plasma. It contains E. coli-expressed recombinant human GM-CSF and antibodies raised against the recombinant factor. It has been shown to quantitate recombinant human GM-CSF accurately. Results obtained using natural human GM-CSF 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 GM-CSF. Range: 7.80 - 500 pg/mL. Sensitivity: 3 pg/mL. Time: 3.5 hours or 4.5 hours