A batch of standard
immunoglobulin was selected as a United States Reference
Hepatitis A Immunoglobulin. Subsequent to its testing in research laboratories, public health laboratories, hospitals and universities throughout North America and Europe, this
immunoglobulin was provided to the World Health Organization and accepted as an International
Hepatitis A Immunoglobulin Reference Preparation. This reference preparation is provided lyophilized in flame-sealed ampules which have been back-filled with
argon. When the contents of one ampule are reconstituted to a volume of 1.0 ml, the reciprocal end-point dilution titer of
anti-HAV in this reference preparation is approximately 1:500 by competitive-inhibition radioimmunoassay (RIA). Based on data in the literature and that obtained from testing more than 200 batches of
immunoglobulin manufactured in the United States between 1967 and 1977, it appears that the level of
anti-HAV in the reference preparation could be achieved in each batch of
immunoglobulin. Standardization will assure the continued and consistent efficacy of
immunoglobulin batches for prophylaxis against
hepatitis A.