Fine Needle Aspiration Cytology (FNAC)

What is FNAC?

Fine Needle Aspiration Cytology (FNAC) of the thyroid is a procedure used to detect the possibility of cancer in a thyroid nodule or to treat thyroid cysts.

The procedure is performed by inserting a fine needle into the thyroid nodule and making several passes to obtain a small sample of tissue to send to the lab for evaluation. The procedure is usually carried out under ultrasound guidance for accurate placement of the needle.

Are there any risks involved?

Thyroid FNAC is generally safe and complications are rare. You may experience mild bruising, bleeding, swelling or pain at the puncture site. It is rare for such bleeding to cause significant swelling and breathing problems.

Carried out under ultrasound guidance, there is a 3-4% risk of having to repeat the FNAC because the sample originally taken was inadequate to make a diagnosis. The rates of complications stated are approximations and may vary depending on the underlying medical condition.

Preparation for FNAC

1. No fasting is required.

2. Remove all jewellery and keep personal valuables at home.

3. Report 15 min before your appointment date and time to Tower B, Level 2 (B25), Diagnostic Radiology.

4. If you are currently on blood thinning medication, please stop taking them as instructed.

What to expect during the procedure?

You may be given local anesthetic injection to numb the injection site. You may feel a slight pin prick from the needle. Your doctor may take several samples from a single or multiple nodules. The procedure is around 15 to 20 minutes.

It will take 1-2 weeks to process the results of the procedure and your doctor will then discuss this with you at the next appointment.

What to expect after the procedure?

• The adhesive dressing over the puncture site is best left in place for 1-2 hours, after which it can be removed, and the area can be washed if required.

• You may notice slight pain with swelling or bruising at the injection site and can alleviate this with simple pain killers like Paracetamol/Panadol.

• You can resume usual activities including eating and drinking. Do not engage in strenuous physical activity (such as heavy lifting or contact sports) for approximately 24 hours after the procedure.

• Seek immediate medical attention by visiting the emergency department if you experience sudden increase in pain or swelling, continued bleeding or difficulty in breathing.

Important discharge info

• You should arrange for a responsible adult (such as a family member, relative or friend) to accompany you home and monitor you subsequently at home. You may be drowsy, or even if you are alert, your judgement and reflexes may be affected for the rest of the day.

• If you decide to go home unaccompanied, you have to plan for and assume responsibility for your own safety and that of others.

• For the next 24 hours following sedation, you must not perform high-risk activities such as driving, riding a bike, operating machinery, climbing ladders, swimming, or signing of important documents.