RIAs

Question 1

What is the technique used for?

Answer 1

used to measure low levels of antigens such as the hormone levels in the blood, by the use of antibodies

Question 2

What is the process of Radioactive immunoassays?

Answer 2

• a known quantity of an antigen is radioactively labelled and mixed with a known quantity of the antibody, they specifically bind together
• a sample from a patient which contains an unknown quantity of the same antigen is then added
• causing the unlabelled antigen from the patient to compete with the labelled antigen to form a antigen-antibody complex
• the bound antigens are separated from unbound antigens and the radioactivity of the bound antigen remaining is measured by a gamma counter

Question 3

What two words describe RIAs?

Answer 3

sensitive and specific

Question 4

What can obstruct with an RIA?

Answer 4

Human antibodies can interfere with an RIA and react either positively or negatively with the immunoassay reagents to give a false result