Human Properdin/Complement Factor P ELISA Kit

A double-antibody sandwich ELISA from Assay Genie designed for the quantitative measurement of human properdin (complement factor P). The colorimetric assay uses TMB substrate development with absorbance read at 450 nm and is validated for use with serum, plasma, cell culture supernatant, cell or tissue lysate, and other liquid samples, with reactivity confirmed for human properdin.

Manufacturer specifications report a sensitivity of 0.938 ng/mL and a standard curve range of 1.563-100 ng/mL. Linearity (n=5) is given as 89-98% at 1:2, 86-100% at 1:4 and 83-98% at 1:8 for serum; 82-100%, 85-100% and 88-97% for EDTA plasma; and 82-96%, 84-99% and 80-99% for heparin plasma. Spike-and-recovery averages are 93% for serum (range 86-103%), 91% for EDTA plasma (range 93-101%) and 96% for heparin plasma (range 86-104%). Unopened components are stated to be stable for 12 months at 2-8°C.

The protocol comprises six steps: equilibrate reagents and TMB substrate to room temperature, then load standards, samples and a blank onto the pre-coated plate and incubate at 37°C for 90 minutes; add biotinylated detection antibody and incubate at 37°C for 60 minutes; add HRP-streptavidin and incubate at 37°C for 30 minutes; develop with TMB substrate in the dark for 10-20 minutes; add stop solution and read absorbance at 450 nm. Properdin is described as a key component of the complement system that enhances immune responses and inflammation, and dysregulation of properdin levels has been implicated in diseases including autoimmune disorders and infections, making it a useful biomarker in immunology research.