Human C3d/Complement Fragment 3d ELISA Kit

Assay Genie's Human C3d (Complement Fragment 3d) ELISA Kit is a sandwich ELISA using a double antibody format for the quantitative measurement of C3d in human samples. The kit is suitable for use with serum, plasma, cell culture supernatant, cell or tissue lysate, and other liquid samples. Reported performance includes a sensitivity of 4.688 ng/mL and a detection range of 7.813-500 ng/mL, with storage at 2-8°C for 12 months.

The assay procedure comprises six steps: equilibrate reagents and TMB substrate to room temperature; primary incubation at 37°C for 90 minutes; biotinylated detection antibody binding at 37°C for 60 minutes; HRP-Streptavidin binding at 37°C for 30 minutes; TMB substrate color development in the dark for 10-20 minutes; and absorbance measurement at 450 nm after adding stop solution. Sample preparation protocols are provided for serum, plasma, tissue homogenate, cell culture supernatant, and cell lysate.

Reported linearity for serum (n=5) at 1:2, 1:4 and 1:8 dilutions is 88-97%, 85-105% and 88-103%; for EDTA plasma (n=5), 82-101%, 83-101% and 85-101%; and for heparin plasma (n=5), 82-94%, 80-100% and 84-98%. Reported recovery for serum (n=5) is 85-104% (average 96%), for EDTA plasma (n=5) is 87-105% (average 99%), and for heparin plasma (n=5) is 89-105% (average 95%). C3d is described as a component of the complement system with roles in immune response and inflammation, and elevated levels have been associated with autoimmune diseases, infections and inflammatory conditions.