- 1. Dosage of thyroid hormones
- 2. Dosage of antibodies
- 3. Ultrasound of the thyroid
- 4. Thyroid scintigraphy
- 5. Thyroid biopsy
- 6. Thyroid self-examination
- When thyroid exams are needed
To identify diseases that affect the thyroid, the doctor may order several tests to assess the size of the glands, the presence of tumors and thyroid function. Thus, the doctor can recommend the measurement of hormones that are directly linked to the functioning of the thyroid, such as TSH, free T4 and T3, as well as imaging tests to check for the presence of nodules, such as thyroid ultrasound, for example.
However, more specific tests may also be ordered, such as scintigraphy, biopsy or antibody test, which may be recommended by the endocrinologist when investigating certain diseases, such as thyroiditis or thyroid tumors, for example. See signs that may indicate thyroid problems.
The most requested tests to evaluate the thyroid are:
1. Dosage of thyroid hormones
The measurement of thyroid hormones through a blood test allows the doctor to evaluate the functioning of the gland, being possible to check if the person has alterations suggestive of hypo or hyperthyroidism, for example.
Although the reference values may vary according to the person's age, presence of pregnancy and laboratory, normal values generally include:
| Thyroid Hormone | Reference value |
| TSH | 0.3 and 4.0 mU / L |
| Total T3 | 80 to 180 ng / dl |
| T3 Free | 2.5 to 4 pg / ml |
|
T4 Total |
4.5 to 12.6 mg / dl |
| T4 Free | 0.9 to 1.8 ng / dl |
After identifying the change in thyroid function, the doctor will assess the need to order other tests that help to identify the cause of these changes, such as ultrasound or antibody measurement, for example.
Understand the possible results of the TSH exam
2. Dosage of antibodies
Blood tests can also be done to measure antibodies against the thyroid, which can be produced by the body in some autoimmune diseases, such as Hashimoto's thyroiditis or Graves' disease, for example. The main ones are:
- Anti-peroxidase antibody (anti-TPO): present in the vast majority of cases of Hashimoto's thyroiditis, a disease that causes cell damage and gradual loss of thyroid function; Anti-thyroglobulin antibody (anti-Tg): it is present in many cases of Hashimoto's thyroiditis, however, it is also found in people without any alteration of the thyroid, therefore, its detection does not always indicate that the disease will develop; Anti-TSH receptor antibody (anti-TRAB): may be present in cases of hyperthyroidism, mainly caused by Graves' disease. Find out what it is and how to treat Graves' disease.
Thyroid autoantibodies should only be requested by doctors in cases where thyroid hormones are altered, or if thyroid disease is suspected, as a way to help clarify the cause.
3. Ultrasound of the thyroid
Ultrasound of the thyroid is done to assess the size of the gland and the presence of changes such as cysts, tumors, goiter or nodules. Although this test cannot tell whether a lesion is cancerous, it is very useful in detecting its characteristics and in guiding the puncture of nodules or cysts to aid in diagnosis.
4. Thyroid scintigraphy
Thyroid scintigraphy is an examination that uses a small amount of radioactive iodine and a special camera to obtain an image of the thyroid, and to identify the level of activity of a nodule.
It is indicated mainly to investigate nodules suspected of cancer or whenever hyperthyroidism is suspected caused by a hormone-secreting nodule, also called a hot or hyperfunctioning nodule. Find out how thyroid scintigraphy is done and how to prepare for the exam.
5. Thyroid biopsy
The biopsy or puncture is done to identify whether the thyroid nodule or cyst is benign or malignant. During the exam, the doctor inserts a fine needle towards the nodule and removes a small amount of the tissue or liquid that forms this nodule, so that this sample is evaluated in the laboratory.
Thyroid biopsy can hurt or cause discomfort because this test is not done under anesthesia and the doctor can move the needle during the test to be able to take samples from various parts of the nodule or to aspirate a larger amount of fluid. The exam is quick and lasts about 10 minutes and then the person must remain with a bandage in place for a few hours.
6. Thyroid self-examination
Self-examination of the thyroid can be done to identify the presence of cysts or nodules in the gland, being important to help detect any changes early and prevent complications of diseases and should be done mainly by women over 35 or with family history of thyroid problems.
To do this, the following steps must be followed:
- Hold a mirror and identify the location where the thyroid is located, which is just below the Adam's apple, known as "gogó"; Tilt your neck back a little, to better expose the region; Drink a sip of water; Observe the movement of the thyroid and identify if there is any protrusion, asymmetry.
If any thyroid abnormality is noted, it is important to seek the attention of the endocrinologist or general practitioner so that the investigation can be carried out with tests that can confirm or not a thyroid alteration.
When thyroid exams are needed
Thyroid exams are indicated for people over 35 years old or earlier if there are symptoms or family history of thyroid changes, women who are pregnant or wishing to become pregnant and for people who noticed changes during self-examination or medical examination of the thyroid.
In addition, tests are also indicated after radiation treatment for neck or head cancer and during treatment with drugs, such as lithium, amiodarone or cytokines, for example, which can interfere with thyroid function.
