The document discusses thyroid stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4) blood tests. TSH is produced in the brain and triggers the thyroid gland to produce T3 and T4, which regulate metabolism. The tests are used to diagnose hyperthyroidism and hypothyroidism, and monitor treatment. Reference ranges, test procedures, and potential signs and symptoms of thyroid disorders are provided.

1. TSH,T3&T4 test
Prepared by: niaz salih
mahmud

2. (TSH) blood test is used to check for thyroid gland problems.
TSH is produced when the hypothalamus
releases a substance called thyrotropin-releasing
hormone (TRH). TRH then triggers the pituitary gland
to release TSH.
TSH causes the thyroid gland to make two hormones:
triiodothyronine (T3) and thyroxine (T4). T3 and T4 help
control your body's metabolism.

4. Why It Is Done
*Find out whether the thyroid gland is working
properly
_An underactive thyroid gland (hypothyroidism)
_An overactive thyroid (hyperthyroidism)
*Find the cause of an underactive thyroid gland
(hypothyroidism).

5. • Keep track of treatment with thyroid replacement medicine for
people who have hypothyroidism.
• Keep track of thyroid gland function in people who are being treated
for hyperthyroidism. This treatment may include antithyroid
medicine, surgery, or radiation therapy.
• Double-check the diagnosis of an underactive thyroid gland in
a newborn(congenital hypothyroidism).

6. How To Prepare
Tell your doctor if you have had any tests in which you were
given radioactive materials or had X-rays that used iodine dye
within the last 4 to 6 weeks. Your test results may not be
correct if you have had iodine contrast material before having
a thyroid-stimulating hormone (TSH) test.

7. How It Is Done
The health professional drawing blood will:
• Wrap an elastic band around your upper arm to stop the flow of blood. This
makes the veins below the band larger so it is easier to put a needle into the
vein.
• Clean the needle site with alcohol.
• Put the needle into the vein. More than one needle stick may be needed.
• Attach a tube to the needle to fill it with blood.
• Remove the band from your arm when enough blood is collected.
• Put a gauze pad or cotton ball over the needle site as the needle is removed.
• Put pressure to the site and then put on a bandage.

8. TSH- Normal range
Until 2002, the official TSH "normal range"
that laboratories and most doctors used
throughout the U.S. was a range of 0.5 to 5.0.
Since late 2002, however, the American
Association of Clinical Endocrinologists (AACE)
and other professional groups have
recommended a narrower range of .3 to 3.0.

10. Free T4 - Free Thyroxine
Free T4 measures the free, unbound thyroxine levels in your
bloodstream. Free T4 is typically elevated in hyperthyroidism, and
lowered in hypothyroidism.
Free or unbound T4 levels represent the level of hormone available
for uptake and use by cells. Bound levels represent a circulating
hormone that may not all be immediately available, because it is
affected by other drugs, illness, and physical changes such as
pregnancy. Because the free levels of T4 represent immediately
available hormone, free T4 is thought to better reflect the patient's
hormonal status than total T4

11. Total T4/Total Thyroxine/Serum Thyroxine
This test measures the total amount of circulating thyroxine in your blood.
Thyroxine, a hormone produced by the thyroid, is also known as T4. A high
value can indicate hyperthyroidism, a low value can indicate hypothyroidism.
Total T4 levels can be elevated due to pregnancy, and other high estrogen
states, including use of estrogen replacement or birth control pills.

12. Total T3-Total Triiodothyronine
Triiodothyronine is the active thyroid
hormone, and is also known as T3. Total T3 is
typically elevated in hyperthyroidism, and
lowered in hypothyroidism.

13. Free T3 - Free Triiodothyronine
Free T3 measures the free, unbound levels of triiodothyronin
in your bloodstream. Free T3 is
considered more accurate than Total T3. Free T3 is typically elevated
in hyperthyroidism, and lowered in
hypothyroidism.

14. T3 &T4-Normal range
T4: Normal Adult Range: 4 - 12 ug/dl Optimal
Adult Reading: 8 ug/dl
T3: Normal Adult Range: 27 - 47% Optimal Adult
Reading: 37 %

15. What does the test result mean?
TSH T4 T3 Interpretation
High Normal Normal Mild (subclinical) hypothyroidism
High Low Low or Hypothyroidism
normal
Low Normal Normal Mild (subclinical) hyperthyroidism
Low High or High or Hyperthyroidism
normal normal
Low Low or Low or Non-thyroidal illness; rare pituitary
normal normal (secondary) hypothyroidism

16. Signs and symptoms of hyperthyroidism may include:
• Increased heart rate
• Anxiety
• Weight loss
• Difficulty sleeping
• Tremors in the hands
• Weakness
• Diarrhea (sometimes)
• Light sensitivity, visual disturbances
• The eyes may be affected: puffiness around the eyes, dryness, irritation, and,
in some cases, bulging of the eyes.

17. Symptoms of hypothyroidism may include:
• Weight gain
• Dry skin
• Constipation
• Cold intolerance
• Puffy skin
• Hair loss
• Fatigue
• Menstrual irregularity in women