CFR›Title 21›Chapter I›Part 660›Subpart A ContainsSections 660.1–660.6CorpusDaily eCFRDisplayed edition2026-04-15Last updated2026-04-15 Subpart A—Antibody to Hepatitis B Surface Antigen Sections 660.1 § 660.1 Antibody to Hepatitis B Surface Antigen. 660.2 § 660.2 General requirements. 660.3 § 660.3 Reference panel. 660.4 § 660.4 Potency test. 660.5 § 660.5 Specificity. 660.6 § 660.6 Samples; protocols; official release. Next C Subpart C—Blood Grouping Reagent