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1. RIA is a test used to measure the concentrations of antigens in the body.

2-4. For the test to be performed, three components should be present. There should be the radiolabeled antigen, the antibody specific to the antigen, and the natural antigen, which is present in the patient's serum.

5. The concentration of the labeled antigen is inversely proportional to the concentration of the natural antigen because these antigens compete for the binding sites of the antibodies.

6-7. The Radioimmunoassay (RIA) technique was made known in the 1950s by Rosalyn Yalow and Solomon Aaron Berson.

8. Rosalyn Yalow developed RIA for the hormone insulin. This became an advancement for testing in the field of endocrinology, which made her a recipient of Nobel Prize in Medicine.

9. Antigens are labeled and made radioactive by the using gamma-radioactive isotopes of iodine, which is then attached to tyrosin.

10. More of the unlabeled antigens ( or "cold" antigens) are binding to the antibodies when its concentration is increased.


CASE STUDY

1. Since there is a lump on the patient's throat, the thyroid might be infected so the thyroid hormone is tested to confirm the patient's condition. The levels of FT3, FT4, TT4 and TSH are measured.

2. The patient's diagnosis is hyperthyroidism. If a patient has hyperthyroidism, the levels of FT3,FT4 and TT4 are increased; while the TSH level is decreased. On the otherhand, in patients with hypothyroidism, the results were opposite. Their FT3, FT4 and TT4 levels are decreased; and their TSH level is increased.

3. There are other tests that can be used in the detection of the thyroid abnormality. Blood samples are usually tested.

• The doctor may request a thyroid scan to check if there are certain abnormalities in the thyroids function and appearance.
• Ultrasound is also requested if there are irregularities in the thyroid. This is a diagnostic test which use a high frequency of soundwaves to create an image of the thyroid.
• CT scan and Magnetic Resonance Imaging (MRI) are also used as a confirmatory test to view the thyroid galnd and see if there are any physical or functional abnormalities.

4. Signs and symptoms may vary depending on the severity of the disease. But comon signs and symptoms are:

• weight loss
• tremors
• vision problems
• shaking
• nervousness
• patient easily gets tired
• exolpthalmia
• goiter or enlargement of thyroid
• diarrhea
• palpitation
• In women, there may be menstrual cycle irregularities.

5. In this test, antigens which are of known amount or quantity are made radioactive. These antigens, which are now radioactive, are then mixed with antibodies of that antigens. Which result the two to bind chemically to one another. Then, a serum sample from a patient which contain an unknown amount or quantity of the same antigens is then added. This cause the unlabeled antigens from the patient's serum to compete with the radiolabeled antigens for binding sites in the antibody.

Reference:

WIKI-RIA

ANSWER.COM-antigen

ANSWER.COM-antibody

CHEMHERITAGE.ORG

WIKI-SOLOMON BERSON

ANSWER.COM-insulin

HMC.PSU.EDU

A SHORT QUIZ ON RADIOIMMUNOASSAY (RIA)

1. This technique measures the concentration of which substance?

2-4. In RIA, what are the three components that should be present for the test to be performed?

5. The concentration of the labeled antigen is (directly/ inversely) proportional to the natural antigen.

6-7. Who developed the RIA technique?

8. One of the developers of RIA received a Nobel Prize for what hormone?

9. What is the reagent or material used for labeling antigens?

10. More of the unlabeled antigens are binding to the antibodies when the unlabeled antigen's concentration is (increased/ decreased).



CASE STUDY

A 20 year old female noticed that there is a lump found on her throat. She also observed that she gained weight in the past weeks. Her hands felt cold and that she was always nervous. She went to the doctor and had her blood tested. Radioimmunoassay was the test performed. The results showed that she has hyperthyroidism.

• What is/are the hormones tested that confirmed the patient's condition?
• What are the expected results in the said condition?
• Are there other test/s that should be done for the confirmation of the patient's condition? Give a brief explanation.
  
• What other signs & symptoms seen in patients with hyperthyroidism?
• In your own words, state the principle of radioimmunoassay.

Reference:
WIKI-RIA

Radioimmunoassay (RIA)

Radioimmunoassay (RIA)

This technique which is very sensitive and is used to measure the concentrations of antigens. Radioimmunoassay technique is a specific and sensitive test, but this technique need a special equipment, which is costly. Substances used in this test are radioactive, so special precautions are to be observed.

Radioimmunoassay or RIA is one of the tests used to help the clinician determine the levels of hormones in a patient. Estrogen is one of these hormone. The level of estrogen is important to be measured because an increase or decrease of its level is unhealthy and may be detrimental to the patient.

Principle:

In this test, antigens which are of known amount or quantity are made radioactive. These antigens, which are now radioactive, are then mixed with antibodies of that antigens. Which result the two to bind chemically to one another. Then, a serum sample from a patient which contain an unknown amount or quantity of the same antigens is then added. This cause the unlabeled antigens from the patient's serum to compete with the radiolabeled antigens for binding sites in the antibody.

Reference:
Wikipedia-RIA