Circumventing complement C3 interference in the analysis of carbohydrate-deficient transferrin in fresh serum

A method for preventing interference by the glycoprotein complement C3 and its beta-globulin split products in the capillary electrophoretic analysis of carbohydrate-deficient transferrin was developed. Inulin was used to activate the alternate complement pathway and convert native C3 into various degradation products whose electrophoretic mobility no longer coincides with the transferrin glycoforms. Capillary electrophoresis and zone electrophoresis on agarose gel were used to monitor reaction conditions for alternate complement pathway activation. Incubation of 50 microL of fresh serum with 180 microL of a 50 mg/mL inulin slurry for 12 h removed the native C3 peak from the beta region. Inulin treatment did not affect electrophoretic behavior of other beta-globulins, including transferrin. Altering the electrophoretic behavior of complement C3, by treating fresh serum with inulin, permits rapid capillary electrophoresis evaluation of carbohydrate-deficient transferrin glycoforms.