Skip to main content
Find a Lawyer

Code of Federal Regulations Title 21. Food and Drugs § 21.660.25 Potency tests without reference preparations

Current as of January 02, 2025 | Updated by Findlaw Staff

Products for which Reference Blood Grouping Reagents are not available shall be tested for potency by a method approved by the Director, Center for Biologics Evaluation and Research.

(a) Potency requirements. Blood Grouping Reagents recommended for the test tube methods, including the indirect antiglobulin tests, shall have the following potency titer values, unless other values are approved by the Director, Center for Biologics Evaluation and Research.

(1) For Anti–K, Anti-k̄, Anti–Jk a, Anti–Fy a, Anti–C w, at least 1+ reaction with a 1:8 dilution of the reagent.

(2) For Anti–S, Anti-s̄, Anti–P1 , Anti–M, Anti–I, Anti-e (saline), Anti-c̄ (saline), and Anti–A1 , at least 1+ reaction with a 1:4 dilution of the reagent.

(3) For Anti–U, Anti–Kpa, Anti–Kpb, Anti–Jsa , Anti–Jsb , Anti–Fyb , Anti–N, Anti–Lea , Anti–Leb , Anti–Lua, Anti–Lub , Anti–Di a , Anti–M g, Anti–Jkb , Anti–Cob, Anti–Wr a, and Anti–Xga, at least 2+ reaction with undiluted reagent.

(b) Products recommended for slide tests or microplate techniques. Blood Grouping Reagent recommended for slide test methods or microplate techniques shall produce clearly positive macroscopic results when both undiluted reagent and reagent diluted with an equal volume of diluent are tested by all methods recommended in the manufacturer's package insert using red blood cells showing heterozygous or diminished expression of the corresponding antigen. The dilution shall be made with an equal volume of compatible serum or approved diluent.

(c) Products recommended for use in an automated system. The manufacturer of Blood Grouping Reagent that is recommended for use in an automated system shall demonstrate that its product when used both undiluted and diluted with an equal volume of diluent satisfactorily performs when tested with cells representing heterozygous or diminished expression of the corresponding antigen.

Previous Part of Code Next Part of Code
Back to Chapter List

Cite this article: FindLaw.com - Code of Federal Regulations Title 21. Food and Drugs § 21.660.25 Potency tests without reference preparations - last updated January 02, 2025 | https://codes.findlaw.com/cfr/title-21-food-and-drugs/cfr-sect-21-660-25/

FindLaw Codes may not reflect the most recent version of the law in your jurisdiction. Please verify the status of the code you are researching with the state legislature before relying on it for your legal needs.

Was this helpful?

Welcome to FindLaw's Cases & Codes

A free source of state and federal court opinions, state laws, and the United States Code. For more information about the legal concepts addressed by these cases and statutes, visit FindLaw’s Learn About the Law.

Go to Learn About the Law

Latest Blog Posts

For Legal Professionals

Learn About The Law

Get help with your legal needs

FindLaw’s Learn About the Law features thousands of informational articles to help you understand your options. And if you’re ready to hire an attorney, find one in your area who can help.

Go to Learn About the Law

Need to Find an Attorney?

Search our directory by legal issue

Enter information in one or both fields (Required)

Copied to clipboard