Hemagglutinin is a
protein which causes
red blood cells to clump together; it causes
hemagglutination. It is often used in
clinical lab tests such as the
hemadsorption test to detect the presence of hemagglutinating
viruses.
From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.