Endocrinology homework
Nisreen Gheithan 22111003
Malak Hammad 22110888
Manar Dar Nafee 22110382
1- RAIU test
RAIU (Radioactive Iodine Uptake) is a medical test used to
evaluate thyroid function. This test measures the amount of
radioactive iodine that the thyroid gland absorbs from the
blood after a small dose of radioactive iodine is ingested or
injected.
Definition of RAIU
1. Purpose of the test: The RAIU test is usually used to
evaluate conditions of hyperthyroidism (such as Graves'
disease), and also to determine thyroid function in people
with problems such as nodules or enlargements.
2. How the test is performed: The patient is given a small
dose of radioactive iodine (usually I-123 or I-131) by mouth
or injection. The amount of iodine absorbed by the thyroid
gland is then measured over a specific period of time
(usually after 4-6 hours and/or 24 hours).
How to evaluate
The results of the RAIU test are evaluated based on the rate
at which the thyroid gland absorbs the radioactive iodine,
which is a measure of its function:
1. Normal uptake: Usually ranges from 10-30% after 24
hours.
2. High absorption results: If the ratio is higher than normal,
this may indicate hyperthyroidism (such as Graves' disease).
3. Low absorption results: If the ratio is lower than normal,
this may indicate hypothyroidism or certain infections of the
gland.
Analyzing the results requires an assessment of clinical
symptoms and the patient's history, and is often used in
conjunction with other tests such as a blood test for thyroid
hormones.
2-Rercholarate test
The perchlorate discharge test (PDT) is commonly used to
evaluate thyroid function, specifically to diagnose conditions
affecting the iodide organification process within the thyroid
gland. This test is particularly useful in diagnosing Pendred
syndrome, a genetic disorder that can lead to both hearing
loss and thyroid dysfunction. Pendred syndrome involves a
defect in the thyroid’s ability to incorporate iodine into
thyroid hormones.
In the test, a radioactive iodine isotope is first administered
to measure thyroid uptake. After some time, potassium
perchlorate is given to the patient. Normally, this does not
affect iodine levels in the thyroid, but in cases like Pendred
syndrome or other iodide organification defects, perchlorate
will cause a rapid reduction in thyroid iodine content. This
outcome indicates an abnormal organification process .
Evaluation of the perchlorate discharge test typically
involves comparing the thyroid’s iodine uptake before and
after administering perchlorate. If iodine levels drop
significantly after perchlorate is introduced, this suggests an
organification defect and supports a diagnosis of disorders
like Pendred syndrome
