Radioimmunoassay notes

1. Radioimmunoassay (RIA)
Dr. sarah abdulsalam

2. Radioimmunoassay (RIA)
• This method is used for the quantitation of
antigens or haptens that can be radioactively
labeled. It is based on the competition for specific
antibody between the labeled (known) and the
unlabeled (unknown) concentration of material.
• The complexes that form between the antigen and
antibody can then be separated and the amount of
radioactivity measured.
• The more unlabeled antigen is present, the less
radioactivity there is in the complex.

3. • The concentration of the unknown (unlabeled)
antigen or hapten is determined by
comparison with the effect of standards.
• RIA is a highly sensitive method and is
commonly used to assay hormones or drugs in
serum.
• The radioallergosorbent test (RAST) is a
specialized RIA that is used to measure the
amount of serum IgE antibody that reacts with
a known allergen (antigen).

4. • RAST test procedure
• The RAST test procedure is fairly straightforward
and does not require any preparation.
• After a person speaks to their doctor, a medical
professional will take a blood sample, usually
from the individual’s arm.
• This blood is then sent to a laboratory, where it is
subjected to a battery of tests that look for
antibodies that have developed in response to
specific allergens