{"data":{"id":"us/21-cfr-660.44","jurisdiction":"us","citation":"21 CFR 660.44","heading":"Specificity.","body":"Each filling of the product shall be specific for Hepatitis B Surface Antigen as determined by specificity tests found acceptable to the Director, Center for Biologics Evaluation and Research.","path":["Title 21—Food and Drugs","CHAPTER I—FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES","SUBCHAPTER F—BIOLOGICS","PART 660—ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS","Subpart E—Hepatitis B Surface Antigen"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-21.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:47Z","sha256":"e19c7430d388afe77549c1e64bc7a28782a8ac5dd704c62f1dfd9df879ddc272","source_id":"us-cfr","stale":true,"prev":"us/21-cfr-660.43","next":"us/21-cfr-660.45"},"notice":"GroundRules: Original legal text. Not legal advice."}