Quantitative colorimetric assay. The Human Cystatin C ELISA is capable of recognizing both recombinant and naturally produced Human Cystatin C proteins. The antigens listed below were tested at 50 ng/ml and did not exhibit significant cross-reactivity or interference.? Human: Cathepsin B, Cathepsin X/Z/P, Cystatin A, Cystatin B, Cystatin D, Cystatin E/M, Cystatin F, Cystatin S, Cystatin SA, Cystatin SN? Murine: Cystatin C. Sample types: cell lysates, plasma, serum. Range: 63 - 2000 pg/ml.