| CF | Complement fixation (CF) | (CF) is an exacting, complex yet sensitive procedure that detects the presence of a specific antigen-antibody reaction by causing the in vitro activation of complement via the classical pathway. If complement is not fixed, lysis of the pre-antibody-coated reagent erythrocytes occurs. Again, crude quantitation of antibodies is possible by determining the highest dilution (titer) at which lysis does not occur. The differentiation of specific antibody isotype is not possible. |