Evans blue


 * For the band, see Evans Blue

T-1824 or Evans Blue, also rendered as Evan's Blue, is an Azo Compound dye which has a very high affinity for serum albumin.

Because of this, it can be useful in physiology in estimating the proportion of body water contained in blood plasma.

Evans blue is also used to assess the permeability of the blood-brain barrier to macromolecules. Because serum albumin cannot cross the barrier, normally the neural tissue remains unstained.

It was named after Herbert McLean Evans, an American chemist.