A simple immunofixation test for induced C3 degradation in disease states (including C3 nephritic factor) and its correlation with kidney biopsy

•Complement dysregulation can be mediated by C3NeF and results in C3 glomerulopathy.•Immunofixation assay can detect C3 degradation products C3c and C3d.•The immunofixation assay results correlate with immunostaining of kidney biopsy.•The immunofixation assay is a simple and reliable technique.•The assay can be performed on a widely available platform.

Complement dysregulation from an uncontrolled activation of the alternate pathway can be mediated by C3 Nephritic Factor and results in C3 glomerulopathy. Identification of C3 degradation products C3c and C3d in patient serum provides evidence of uncontrolled complement activation. It is possible to detect C3c and C3d in patient serum by an immunofixation assay which induces in vitro C3 degradation. The clinical performance of the immunofixation assay has been assessed by comparing the assay results with findings from immunostaining of kidney biopsies. The immunofixation assay is a simple and reliable technique for detection of C3 degradation on a widely available platform and can be used to provide corroborative evidence of acquired complement dysregulation in patients with C3 glomerulopathy.