Evans blue

n.

A diazo dye used to determine blood volume on the basis of the dilution of a standard solution of the dye in the plasma after its intravenous injection; it is also used as a vital stain for following diffusion through blood vessel walls.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.