Recommended concentrations for use are approximate values. Dilute the antigen preparation at least 10 to 20-fold in PBS for solid phase antigen-antibody titration assays. A dose dependent response assay should be performed to determine the optimal concentration for use in specific applications.HCV core protein shows relatively strong biding specificity for HCV-specific human antibodies. ELISA and Western ELISA require protein in 10ng range depending on the nature and affinity of the secondary detection reagent. HCV converted human serum polyclonal antibodies yield titers of 1:10, 000 or greater at 100ng of immobilized protein under standard ELISA conditions.