Measurement of Antignen and Antibody

Many methods are available for the measurement of antigen and antibody participating in the reactions.

Measurement may be in terms of mass or more commonly as units or titer.

The antibody titer of a serum is the highest dilution of the serum which gives an observable reaction with antigen in the particular reac-tion

The titer of a serum is influenced by the nature and the type and conditions of the test

There are two important parameters of serological tests. They are sensitivity and specificity. Sensitivity refers to the ability of the test to detect even very minute quantity of the antigen or antibody.

Specificity refers to the ability of the test to detect reactions be-tween homologous antigens and antibodies only.