pseudoreaction

[sōō′dō-rē-ăkshən]
n.
  1. A reaction not caused by the substances used in a given test but rather by impurities or other materials in the test medium; a false reaction.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.