Nomenclature for Monoclonal Blood Grouping Reagents
(9/28/92)

Date:     9/28/92

From:     Director, Center for Biologics Evaluation and
          Research

Subject:  Nomenclature for Monoclonal Blood Grouping Reagents

To:       U.S. Licensed Manufacturers of Blood Grouping
          Reagents


During the November 1990 workshop, "Reagents for the 1990's",
questions arose regarding the appropriate nomenclature for the
Monoclonal Blood Grouping Reagent that replaces group O sera
(anti-A,B) and reacts with both the A antigen and its subgroups
as well as the B antigen and its subgroups.  This product is
currently called "Anti-A and B" in the United States when the
source material is monoclonal antibody or a blend of monoclonal
antibodies; some countries have called it "Anti-A/B" or    
"Anti-A+B".  The corresponding polyclonal products have always
been labeled "Anti-A,B" in the United States.

Consistent with the comments presented at the workshop, the
Center for Biologics Evaluation and Research (CBER) recommends
the following nomenclature changes to afford consistency,
facilitate labeling, and eliminate consumer confusion.

     Blood Grouping Reagent which reacts with both the A
     antigen and its subgroups as well as the B antigen
     and its subgroups, regardless of its source, should
     be called   "Anti-A,B."  Reactivity with a majority
     of group A(x) cells is required and must be
     documented.  Claims of reactivity with any other
     subgroups must be documented as well.  

     The labeling must indicate if the source material is
     a single monoclonal antibody or a blend of two or
     more such antibodies.  However, indication that the
     product consists of a blend of two or more monoclonal
     antibodies need not appear in the proper name of the
     product, provided an accurate description is included
     in the "Reagents" section of the package insert.
 
     The term "Anti-A and B" can be phased out by
     manufacturers as they exhaust their labeling
     supplies, since the package insert will continue to
     permit consumers to determine the specific reactivity
     of each product.  As a result, the availability of
     products with both kinds of labeling for a short
     period of time will not cause confusion.


     Manufacturers of product for further manufacturing
     use may request approval for the use of other
     nomenclature, provided appropriate rationale and data
     in support of the request are supplied.

Requests to change the labeling of "Anti-A and B" to "Anti-A,B"
or for the use of other nomenclature should be submitted as part
of the Transmittal of Labels and Circulars, FORM FDA 2567 for
review and approval by CBER.  All changes should be highlighted
in each labeling submission to expedite review and approval.



                         ______________________
                         Kathryn C. Zoon, Ph.D.