Investigations of thyroid nodules

This leaflet will explain the following.

• What the thyroid gland is and what it does.

• What tests you may need to have.

• What could happen if you choose not to have the tests.

• How you may feel after the fine needle aspiration biopsy (FNAC).

• What your results mean.

We hope this leaflet answers some of the questions you may have. If you have any further questions or concerns, please speak to a member of your healthcare team. Their contact details are listed at the end of this leaflet.

Please be aware you may be contacted at short notice to come to hospital for one of these tests. Any telephone calls from the hospital will come from withheld numbers.

It may not be possible for all investigations to be completed at the hospital nearest your home.

What is the thyroid gland? And, what does it do?

Why have I been referred for these tests?

Thyroid nodules are very common, but we are checking to see if your nodule could be cancer.

What tests do I need to have?

Your doctor will discuss with you the tests they would like you to have. These tests may include the following.

• Thyroid function tests are blood tests that measure blood levels of:

  • thyroid-stimulating hormone (TSH); and

  • thyroxine (a hormone produced by your thyroid gland).

  The results of these tests can show whether you have:

  • hyperthyroidism (too much thyroxine); or

  • hypothyroidism (too little thyroxine).

  This test may already have been done by your GP.

• An ultrasound scan uses high-frequency sound waves to produce images of your thyroid gland. A thyroid ultrasound gives the best information about the shape, size, and structure of the nodules.

  Your doctor may use an ultrasound to distinguish cysts from solid nodules, or to see if you have multiple nodules. Doctors may also use it as a guide when performing a fine-needle aspiration biopsy. This scan is carried out in the Ultrasound Department by a radiologist. There are no known risks to having this scan.

• Fine-needle aspiration biopsy (FNAC). Nodules are often biopsied to make sure no cancer is present. During an FNAC, your doctor inserts a small needle into the nodule and removes a sample of cells.

  This procedure is often done at the same time as the ultrasound. It takes about 20 minutes and is very safe. The samples taken will be sent to the Pathology Department. Your results will be sent to the doctor who referred you.

  It may not be possible to complete the FNAC at the same time as your scan. You may be asked to return another time.

  If you take any blood thinning medications, we may ask you to stop taking these before your appointment. We should discuss this with you when we contact you to book your FNAC appointment.

  There is a small risk of some bruising or bleeding at the biopsy site.

Once your doctor has the results of the above tests, they may decide that you need to have further tests / investigations, such as a CT or MRI scan. If this is needed, your doctor will discuss the reasons for this with you.

What happens if I choose not to have these tests?

The blood test checks how your thyroid is working. It is important to check if you have an underactive or overactive thyroid. If your thyroid is left untreated it can cause you other health problems, including blood clots, heart disease, or stroke.

The ultrasound scan will give us information about the nodules, including their shape and size. A large non-cancerous nodule can still cause discomfort or problems with swallowing. This is because of the pressure it places on your oesophagus (food pipe).

Will I have an anaesthetic before my FNAC?

You may be offered a local anaesthetic for the FNAC, but many patients do not need this. A local anaesthetic will numb the area, but you will be awake for the procedure. If you have any concerns about this, please speak to your doctor.

You can eat and drink as normal before this procedure.

How will I feel after the FNAC?

• After your FNAC, you may be asked to wait in the Ultrasound Department for up to 30 minutes. After this time you can go home.

• You should not feel any pain, but you may have some slight discomfort at the biopsy site.

• You can drive home from the hospital, and return to work after your procedure.

Can I eat after my procedure?

Yes. You can eat and drink normally after your procedure

If I need to, is it safe for me to take painkillers?

Yes. If you do have any discomfort after your procedure, you can take painkillers (such as paracetamol).

How long will it take to get the results of my tests?

The radiologist may be able to tell you what they have seen on the ultrasound scan after your scan is completed. However, patients often need to wait for a formal report to be sent to the doctor who requested their scan.

If your doctor needs to compare the results with any of your previous scans, this can take longer.

If an FNAC is taken, the results of this will take about 2 weeks. The results will be discussed with you at your next appointment.

We will arrange a follow-up appointment with you to discuss your results. This may be a face-to-face appointment or a telephone consultation with one of the doctors or a clinical nurse specialist (CNS).

What happens after my tests?

The results of your ultrasound will give us a detailed report about your thyroid. We will be able to see:

• any nodules

• the size of the nodules, and

• if there are any concerns.

The FNAC will give us information about the structure of the nodule, and if there is any concern that it may be thyroid cancer.

The results of these tests will help us to decide if we need to offer you any further investigations or treatment for your nodules.

What do my results mean?

Your test results are graded. What these grades mean is explained below.

• Thy1: non-diagnostic. There are not enough cells in the sample. Your doctor / CNS may recommend that your biopsy is repeated.

• Thy1 c is likely to show that you have a benign (not harmful) thyroid cyst. The doctor / CNS will discuss with you whether you need any further monitoring.

• Thy2 is benign (not harmful) thyroid cells. Depending on the size of the nodule, we will discuss with you if you need any further investigations. Your doctor / CNS may recommend that we continue to monitor you or you may be discharged from our care.

• Thy3. Some changes can be seen in the cells since your last scan. The changes can be for many reasons but we cannot rule out cancer. We may discuss with you having surgery to remove part (hemithyroidectomy) or all of your thyroid (total thyroidectomy).

• Thy4: suspicious of cancer. It is likely that we will discuss surgery with you to remove part (hemithyroidectomy) or all of your thyroid (total thyroidectomy).

• Thy5: almost definitely cancer. It is likely that we will discuss surgery with you to remove part (hemithyroidectomy) or all of your thyroid (total thyroidectomy).

The doctor or CNS will discuss your results with you and the next steps in your treatment. If you have any questions or concerns about your results, please speak to them.

Further investigations or treatment may not be needed. Nodules in the thyroid are very common. They often do not need any treatment or investigations, other than thyroid function tests and an ultrasound. This will be discussed with you at your follow-up appointment.

What if my results show no concerns, but I still have a thyroid lump / swelling?

If all your investigations are reassuring and the thyroid lump or swelling is not causing any problems, you may not need treatment. The doctor / CNS will discuss with you if you need to be monitored. If you do not need monitoring, you will be discharged to the care of your GP. Your GP can refer you to us again if there is any further concern or the lump grows.

Sometimes the size of the lump may be monitored with follow-up scans. In some cases your doctor may suggest surgery.

What happens now?

We understand that undergoing investigations can be a stressful time. Please talk to your doctor or CNS about any concerns you have, so that they can help you.

We will speak with you about all your treatment options. If you need time to consider your options we can arrange a further appointment for you. Use this time to ask hospital staff any further questions or raise concerns. Remember you have the right to withdraw your consent for treatment at any time.

Further information

• British Thyroid Foundation

[Web site last accessed 10 March 2026]

What if I have any questions or concerns about my condition or treatment?

If you have any questions or concerns about the tests discussed in this leaflet, please contact your consultant’s secretary. The secretary will be able to arrange for someone to discuss your concerns with you.

• Mr Theokli (secretary)
  Telephone: 01227 783011

• Mr Balfour (secretary)
  Telephone: 01227 864105

• Mr Dhar (secretary)
  Telephone: 01227 783085

• Mr Hone (secretary)
  Telephone: 01227 786351

• Mr Al-Lami (secretary)
  Telephone: 01227 786351

Ask 3 Questions

There may be choices to make about your healthcare. Before making any decisions, make sure you get the answers to these three questions:

• What are my choices?

• What is good and bad about each choice?

• How do I get support to help me make a decision that is right for me?

Your healthcare team needs you to tell them what is important to you. It’s all about shared decision making.

What do you think of this leaflet?

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• Patient Voice Team
  Telephone: 01227 868605
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