» Anti-B Blood Grouping Serum conforms to the regulations of the federal Food and Drug Administration concerning biologics (660.20 to 660.29) (see Biologics 1041). It is a sterile, liquid or dried preparation containing the particular blood group antibodies derived from high-titered blood plasma or serum of human subjects, with or without stimulation by the injection of Blood Group Specific Substance B (or AB). It agglutinates human red cells containing B-antigens, i.e., blood groups B and AB (including subgroups A1B and A2B). It contains a suitable antimicrobial preservative. It meets the requirements of the test for potency, in parallel with, and not less than equivalent to, the U.S. Reference Blood Grouping Serum Anti-B, in agglutinating red blood cells from Group B donors. It meets the requirements of the tests for specificity with Group A1, B, and O cells and confirms the absence of contaminating antibodies reactive with Mg, Wra antigens as well as other antigens having an incidence of 1 percent or greater in the general population (see under Blood Grouping Serums Anti-D, Anti-C, Anti-E, Anti-c, Anti-e). It meets the requirements of the test for avidity with Group B cells. All fresh or frozen red blood cell suspensions used for these tests are prepared under specified conditions and meet specified criteria. Anti-B Blood Grouping Serum may be artificially colored yellow.