Our anti-human C1q antiserum is sourced from goats immunized with purified human C1q. After solid-phase adsorption, it’s reacted with fluorescein isothiocyanate. Excess dye is removed by dialysis, and the conjugated globulin is further purified on DEAE cellulose. Total protein is quantified using the Biuret reaction, and fluorescein concentration is determined by comparison with a fluorescein diacetate standard. Sodium azide (0.1% w/v) is included as a preservative.