The Quantikine Human Cystatin B Immunoassay is a 4.5 hour solid phase ELISA designed to measure Cystatin B levels in cell culture supernates, serum, plasma, saliva, urine, and human milk. It contains E. coli-expressed recombinant human Cystatin B and antibodies raised against the recombinant protein. Results obtained for naturally occurring human Cystatin B and recombinant human Cystatin B showed linear curves that were parallel to the standard curves obtained using the Quantikine Human Cystatin B Immunoassay standards. These results indicate that this kit can be used to determine relative mass values for natural human Cystatin B. Range: 0.16 - 10 ng/mL. Sensitivity: 0.034 ng/mL. Time: 4.5 hours