A collaborative study to establish an International Standard Rabies immunoglobulin of human origin.

Because the supply of the International Standard for Anti-rabies Serum was very low, the WHO initiated a search for a replacement product. The US Food and Drug Administration agreed to undertake a collaborative study using a human rabies immunoglobulin previously purchased for use as a US standard. The potency of this product was determined, in International Units (IU) per millilitre using the rapid fluorescent focus inhibition test for measuring rabies antibody. The mean potency value was found to be 59 IU per ampoule. In June 1984 this preparation was accepted by WHO as the International Standard for Rabies Immunoglobulin.