international unit

international unit definition - medical

international unit

noun Abbr. IU
  1. The quantity of a biologically active substance, such as a hormone or vitamin, required to produce a specific response.
  2. A unit of potency for similarly active substances, based on this quantity and accepted as an international standard.

The American Heritage® Medical Dictionary Copyright © 2009 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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