During an examination of the neck, the thyroid gland, throat, and lymph nodes in the neck are checked by the doctor to examine for unusual growths or swelling. If the doctor feels like doing surgery is required then, the larynx may be examined at the same time with a laryngoscope.

A blood test consists of several different tests, as listed below:

Thyroid hormone levels:
Thyroid hormones are responsible for regulating metabolism. As a result, the doctor will use this test to check the levels of triiodothyronine (T3) and thyroxine (T4) in the body.

Thyroid-stimulating hormone (TSH).:
TSH is a hormone produced by the pituitary gland near the brain. This blood test helps in measuring the level of TSH.

Tg and TgAb:
Thyroglobulin (Tg) is a protein produced by the thyroid. In the body, thyroglobulin antibodies (TgAb) are produced in order to attack thyroglobulin (Tg).

Thyroglobulin (Tg) levels in the body should be low after treatment. In case it continues to increase, more cancer is present. In order to measure Tg levels in the body, a tumor marker test can be performed.

Biopsies are performed under a microscope to examine tissue samples. Cancer can be detected through other tests, but only a biopsy can confirm a diagnosis. An examination of a nodule with a biopsy can reveal whether it is cancerous or benign.

A biopsy can be done in 2 ways for Thyroid Nodules:
1. Surgical biopsy
2. Fine needle aspiration

By using sound waves, an ultrasound creates a picture of the internal organs to determine if cancer has spread. Over the neck area, an ultrasound probe is guided over the skin. With high-frequency sound waves, the doctor can observe the size of the thyroid gland and any nodules, including whether they are solid or fluid-filled sacs called cysts, and diagnose accordingly.

A small amount of radiation can be used to create an x-ray image to show the internal structures of a person. This can give us perfect pictures of the neck, and examine the thyroid gland.

CT scans use x-rays taken from various angles to take pictures of the inside of the body. These images are then combined by a computer into a detailed, three-dimensional image. The size of the tumor can be measured with a CT scan.  
In thyroid cancer patients, CT scans are used to examine parts of the neck that are not visible with ultrasound

In a PET scan, organs and tissues are visualized inside the body. The patient is injected with a small amount of radioactive sugar substance. Using a scanner, the inside of the body is visualized by detecting this substance.