How a thyroid biopsy works: the day, the wait, and the report

Short answer: If you have a thyroid biopsy coming up, it's almost always a fine needle aspiration (FNA): a thin needle takes cells from a thyroid nodule so a specialist can look at them under a microscope. The American Thyroid Association (ATA) says it's done in the doctor's office, usually under ultrasound guidance, and usually lasts less than 30 minutes. The result can take a few days to two weeks, and the report names one of six Bethesda categories.

• The day: you lie on your back with your neck stretched, and the needle goes into the nodule usually between two and six times, per the ATA.
• The wait: a few days to two weeks, and the result can reach your patient portal before anyone has called you.
• The report: a cytopathologist reads the cells and names one category from the Bethesda System, whose 2023 edition publishes an average risk of cancer for each one across studies.

What is a thyroid biopsy, and why was one ordered?

A biopsy date on the calendar and an ultrasound report you only half understood is a lot to carry into one week.

MedlinePlus, the National Library of Medicine's health site, calls fine needle aspiration of the thyroid "a procedure to remove thyroid cells for examination." It says it's often used to find out whether nodules your provider can feel or see on an ultrasound are noncancerous or cancerous.

The American College of Radiology, or ACR, built its TI-RADS system to score how a nodule looks on ultrasound and "to inform practitioners about which nodules warrant biopsy." We went through the ultrasound report and its TI-RADS levels in thyroid nodules with Hashimoto's.

What should you get ready before the appointment?

Your clinic's instruction sheet is the one that applies to you. The ATA, MedlinePlus and RadiologyInfo, the patient site of the ACR and the Radiological Society of North America, describe much the same asks.

• Every medicine you take. MedlinePlus asks that your provider have a current list of all your medicines, "including herbal remedies and over-the-counter medicines," and that you mention medicine allergies, bleeding problems or pregnancy.
• Blood thinners, by name. The ATA says most medications can be continued, but blood thinners "often need to be stopped temporarily" because they can increase the risk of bleeding. MedlinePlus says you may be asked to stop them a few days to a week before, and adds: "Be sure to talk with your provider before stopping any medicines." Whether that applies to you is a question for the doctor who prescribed them.
• Food. The ATA says you generally won't need to fast. Cleveland Clinic says that unless your provider tells you otherwise, you should be able to eat and drink normally.
• Your ultrasound report. Bring a copy with its date and TI-RADS level, so you and the person doing the biopsy are looking at the same page.

The written list to keep for the clinic: write down the medicines list the clinic asks for and your own questions, bring the ultrasound report, and plan a place to file the cytology report with your other dated results for the next visit. Two questions worth adding: who will call you with the result, and whether it can reach your portal first. Our guide to preparing for a thyroid appointment has more on getting questions into the room.

What happens during a thyroid biopsy?

The ATA, RadiologyInfo and MedlinePlus describe the same basic order.

1. You lie down. The ATA says you lie on your back with your head tipped backwards so your neck is extended, and gel goes on your neck for the ultrasound.
2. The skin may or may not be numbed. The sources disagree. Cleveland Clinic lists local anesthesia as a routine step. MedlinePlus says numbing medicine may or may not be used, because the needle is very thin. Ask your clinic which it does.
3. The needle goes in, a few times. The ATA asks you to avoid coughing, talking and swallowing. It says the needle is smaller in diameter than those used in most blood draws, and it samples various parts of the nodule usually between two and six times. RadiologyInfo says a specially trained radiologist most often does it.
4. You go home. It's usually an outpatient visit, and the ATA and RadiologyInfo both put it under 30 minutes. Cleveland Clinic puts it at about 10 to 20 minutes.

You're awake the whole time. The ATA says no medicines are used that affect consciousness or thinking. MedlinePlus says you may feel a sting if numbing medicine is used, and as the needle passes into your thyroid "you may feel some pressure, but it should not be painful."

What is recovery like after a thyroid biopsy?

Short, for most people. The ATA says most patients leave feeling well, there are "very few, if any, restrictions" afterward, and it isn't generally necessary to bring someone to drive you home. The site can be sore and tender for one to two days, per RadiologyInfo, with slight bruising that MedlinePlus says soon goes away.

RadiologyInfo says aftercare instructions vary, though generally you can go back to normal activities and take any bandage off within a few hours. Follow the sheet your clinic hands you.

MedlinePlus says the main risk is bleeding into or around the thyroid gland, and that severe bleeding can press on the windpipe, which it calls rare. Cleveland Clinic asks you to let your provider know about signs of infection, such as fever, chills, or redness, swelling or pus at the site. Before you leave, ask who to call if something feels off.

When does the result arrive, and how?

The wait. Anywhere from a few days to two weeks, per the ATA, though Cleveland Clinic says most people get their result within one week. Cedars-Sinai's advice is to ask your doctor when to expect it, and that's the number that counts for you.

Who tells you. RadiologyInfo says that, depending on the facility, the radiologist or your referring physician will discuss the results with you.

The portal. A result can appear in your patient portal before the doctor has explained it. The federal information-blocking rules from the HHS Office of the National Coordinator for Health IT (ONC) sit behind this. ONC's own FAQ says the rules don't require providers to push results out on their own, but once you request them they must respond in a timely way, which in practice can mean a patient sees a test result in parallel with the clinician who ordered it.

Some health systems now release results, pathology included, as soon as they're final. A 2023 study from the University of Iowa describes its health system moving anatomic pathology results, a category it says covers cytopathology, to immediate portal release on March 9, 2021. In a 2023 survey of 8,139 patients at four US academic medical centers, 96% preferred getting results online right away, even before their clinician had reviewed them, while more worry was reported by 16.5% of those with abnormal results than by 5.0% of those with normal ones.

So ask the clinic before the biopsy who will call you, and whether the result can land in your portal first. ONC says a delay the patient herself asks for "would likely not be an interference" under the rules, so if you'd rather hear it from a person first, ask whether that's possible.

How do you read a thyroid cytology report?

The ATA says cytopathologists make slides from the sample and examine them under a microscope. The report puts the result into one of six categories from The Bethesda System for Reporting Thyroid Cytopathology. The 2023 edition gave each category a single name, per its PubMed abstract, and lists the six as (i) to (vi). Your report will name the category. Papers number them I to VI, but a 2023 open-access review by Beatrix Cochand-Priollet, one of the system's authors, and Zahra Maleki says the report itself shouldn't carry a number. Under the name, the report can add a more specific line, such as "Suspicious for papillary thyroid carcinoma" under Suspicious for malignancy.

The table uses the 2023 system's published figures, as that review reproduces them. A 2026 study from AIIMS Bilaspur in India restates the averages for four of the six rows. The percentages are averages across studies for a category, not your personal risk. Your doctor reads the category alongside your ultrasound and other findings. We read both on November 10, 2026.

The review labels that last column usual management "based exclusively on cytology." Two rows in plainer words: for Nondiagnostic, the ATA says there weren't enough cells to make a diagnosis, which can happen when only cyst fluid is drawn or with too much blood in the sample. For Follicular neoplasm, the ATA describes the surgery, when needed, as removing half of the thyroid, the side with the nodule, for diagnosis and treatment.

Older reports use older names. The 2023 edition dropped the two-name labels of the 2017 version, per the Cochand-Priollet review. Nondiagnostic replaces "Nondiagnostic/Unsatisfactory", AUS replaces "AUS/FLUS", and Follicular neoplasm replaces "FN/SFN". "Hürthle cell" is gone too, replaced by "oncocytic", to align with the 2022 World Health Organization classification. If you've read a page with different percentages, the edition is one reason: the ATA's own FNA patient page still uses the AUS/FLUS name and older ranges, and notes that figures may be somewhat different at different institutions.

One question worth asking comes from the National Cancer Institute (NCI). Its patient guide says that because the type of thyroid cancer can be hard to diagnose, patients should ask to have biopsy samples checked by a pathologist who has experience diagnosing thyroid cancer.

If you already have Hashimoto's, what might the report say?

Nodules and Hashimoto's can turn up in the same neck. The ATA says Hashimoto's thyroiditis "is associated with an increased risk of thyroid nodules." That says nothing about why any one nodule is there.

On the cytology report itself, Hashimoto's (lymphocytic thyroiditis) is worded under the Benign category, per the Bethesda 2023 table: "Consistent with chronic lymphocytic (Hashimoto) thyroiditis in the proper clinical context." The Cochand-Priollet review says a Benign result should specify whether it's a follicular nodule or thyroiditis.

Hashimoto's can also make the cells harder to read. A 2025 review in Cancer Cytopathology from McGill University says lymphocytic thyroiditis "often contains a variable component of oncocytic cells," and that when those cells are numerous, the sample can look almost exactly like an oncocytic follicular neoplasm. When its authors are unsure, they write that they prefer category III over the benign category II. The Cochand-Priollet review places oncocytic cells in the setting of Hashimoto's under the "AUS other" subgroup.

So if you have Hashimoto's and your report says AUS, two questions are fair to bring: did the thyroiditis affect how the sample was read, and what comes next for this nodule?

How do you keep the reports together?

Keep the cytology report next to the ultrasound report and its TI-RADS level. The ultrasound says how the nodule looked. The cytology says what the cells looked like. What goes in the file:

• The ultrasound report: its date, which nodule, and the TI-RADS level as written.
• The cytology report: its date, the category name as printed, and the line under it.
• How it reached you: the date it landed in the portal, and the date someone talked you through it.
• Blood results from around then: TSH and any antibody tests, each with its date and the range your lab printed.

Each provider's portal holds only that provider's results, so the record that spans all of them has to be yours. If older reports are scattered, we wrote about getting your thyroid lab history back from each place.

Osmi doesn't read biopsy reports. Osmi never diagnoses or grades anything; it records what a number is and what's worth asking. Its lab album keeps your blood results, such as TSH or thyroid antibodies, each on its own card against the range your own lab printed. The appointment sheet puts the three questions you write yourself beside your record, on one page you can share with your practitioner in one tap.

Keep the paper or PDF cytology report with your ultrasound report.

Questions women ask about thyroid biopsies

Does a thyroid biopsy hurt? You may feel a sting if numbing medicine is used, then some pressure as the needle passes into your thyroid, "but it should not be painful," per MedlinePlus. Afterward, RadiologyInfo says the site may be sore for one to two days.

How long does a thyroid biopsy take? The ATA and RadiologyInfo both put it under 30 minutes, and Cleveland Clinic puts it at about 10 to 20 minutes. Cleveland Clinic adds that the process may be repeated if you have more than one nodule. You're awake, and you go home the same day.

What should you not do after a thyroid biopsy? The ATA says there are very few, if any, restrictions, and RadiologyInfo says you can generally resume normal activities, though it notes that aftercare instructions vary. Your own clinic's aftercare sheet is the one to follow, and it should say who to call about fever, swelling or pus.

How long do thyroid biopsy results take? Anywhere from a few days to two weeks, per the ATA, though Cleveland Clinic says most people get results within one week. The result can reach your patient portal before your doctor calls, so ask the clinic ahead of time who will talk you through it.

How often does a thyroid FNA show cancer? The ATA says that by age 60 about half of all people have a thyroid nodule, and that over 90% of such nodules are benign. That's more than nine in every ten. For a biopsied nodule, the 2023 Bethesda System publishes an average risk of cancer across studies for each of its six categories, from 4% for Benign to 97% for Malignant. Those averages aren't your personal risk, and your doctor reads the category alongside your ultrasound.

What's the difference between a core needle biopsy and FNA? Cleveland Clinic says nearly all thyroid nodule biopsies use the FNA method, and that a core needle biopsy uses a larger needle, 14- to 20-gauge, for larger, more intact tissue samples. A January 2022 summary in the ATA's Clinical Thyroidology for the Public says it carries a higher risk of complications and is supported by many organizations as a second-line test when FNA isn't diagnostic.

What is molecular testing on a thyroid biopsy? The ATA says several molecular tests can help determine whether some nodules are cancerous or benign, and its nodule page says they're "particularly helpful when the specimen evaluated by the pathologist is indeterminate." It says the person doing the biopsy may take an additional needle pass for the test, at the first biopsy or a repeat one.

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Educational, not medical advice.