Hemagglutination inhibition test

Hemagglutination inhibition test of different influenza samples, diluted from left to right

The hemagglutination inhibition test (HHT, HAHT, also Hirst test) is based on the fact that the blood-clotting ( hemagglutinating ) effect of some viruses is inhibited by antibodies that bind to the hemagglutinating virus components.

Antigens with hemagglutinating properties occur, for example, in the influenza virus (due to the hemagglutinin ) and rubella virus . If a patient's serum can prevent hemagglutination by a virus, this is an indication that the patient has developed specific antibodies when infected with such a virus.

The HHT titer (also HAHT titer) is the reciprocal value of the highest serum dilution at which hemagglutination is still prevented.

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !