A new diagnostic test for thyroid nodules is being trialled at eight NHS Foundation Trusts in England.

If successful, ThyroidPrint could make it easier for doctors to determine whether a thyroid nodule is benign (not cancer) or malignant (cancer). 

We asked Leonie Wheeldon, Consultant Biomedical Scientist at the Royal Cornwall Hospitals NHS Trust about the trial she is coordinating.

How difficult is it to accurately test thyroid nodules?

Thyroid nodules are incredibly common and most of them are benign. As part of the investigation process, patients with thyroid nodules are often referred for a Fine Needle Aspiration (FNA) under ultrasound guidance. This involves using a small needle to obtain a cell sample for microscopic evaluation (Cytological assessment). FNA  is highly effective in diagnosing benign lesions and malignant lesions.

(Caption: Leonie Wheeldon, trial chief investigator)

However,  in a minority of nodules we just can’t tell by looking at the cells if they are cancerous or benign. This is because they look very similar. These nodules are known as THY3, or indeterminate, lesions and they represent about 25% of all thyroid lesions sampled.

Currently, the only way we can give a definitive diagnosis for these types of nodules is by removing half or all of the thyroid (hemithyroidectomy or total thyroidectomy). This gives us much more information about how the lesion is behaving in the organ. For example, we look at whether the lesional cells have spread through the capsule of the nodule (which is classed as cancerous) or not.

How does the ThyroidPrint molecular test work?

In this study, if the FNA classifies the sample as indeterminate then we will use the ThyroidPrint molecular test to help us better understand and risk score the lesion. 

The test uses quantitative real-time polymerase chain reaction (qRT-PCR) which is used to detect and quantify RNA (single strands of DNA) in cell samples. This gives us valuable information about all the genes in cells that are making messenger RNA. Messenger RNA  is a kind of instruction manual for the cell. It contains the genetic information that cells need to make proteins. This information gives us an understanding of how the cell functions and behaves.

The Thyroidprint test is a rapid test which can be performed locally. If this study is successful patients will have conclusive results on the risk score of their indeterminate nodule within days. This will reduce prolonged patient anxiety that can develop before and after surgery whilst waiting to find out if the nodule is cancer or not.

What potential benefits does it offer to patients?

Data tell us that 75% of thyroid lesions will be diagnosed as benign on excision. This suggests that most patients undergo surgery unnecessarily.

If the study is successful,  75% of patients who have a cytologically indeterminate sample will not need to have surgery. We will have a good indication using the ThyroidPrint test if the lesion is benign and can be left alone. This will also reduce pressures and costs on the NHS. 

How much more accurate is it than FNA? 

The ThyroidPrint test is not intended to replace the cytological assessment of the FNA sample. It will complement it. The FNA sample will still be required to look at the cells. If the cytologists categorise these as indeterminate then a ThyroidPrint test will be requested to further risk stratify the lesion.

Initial data from ThyroidPrint studies elsewhere in the world have shown is highly accurate at predicting if the nodule is benign or not. 

Is it already being used successfully outside the UK?

It is routinely being used in Spain and Chile and there are other ongoing trials in Asia and Europe. 

Which hospitals are involved in the trial?

We have an amazing group of NHS pathologists, radiologists, surgeons, biomedical scientists and research teams all working together to ensure the successful delivery of the study. The following trusts are involved in the trial:

Barking, Havering and Redbridge University Hospitals NHS Trust
Blackburn Teaching Hospitals NHS Foundation Trust
East and North Hertfordshire NHS Trust
Gloucestershire Hospitals NHS Foundation Trust
Guy’s and St Thomas’ NHS Foundation Trust
Royal Cornwall Hospitals NHS Trust
Royal Devon University Healthcare NHS Foundation Trust (Exeter)
University College London Hospitals NHS Foundation Trust
University Hospitals of Morecombe Bay NHS Foundation Trust (Lancaster)
University Southampton NHS Foundation Trust

Is the trial suitable for all thyroid lumps? 

The study is only suitable for thyroid lumps classified as indeterminate on ultrasound and FNA testing.  These are more often ‘cold’  or ‘non-toxic’ nodules i.e. where there is no change to thyroid function. 

Are eligible patients able to opt-in to the trial?

Eligible patients being treated at the study sites will be asked for their permission to participate as part of their routine diagnostic testing for their thyroid nodule.  

We are unable to accept patients who are out of the area of a trial site and participants will not be informed of their individual results, nor will it impact on their treatment options as we are still validating the effectiveness and safety of the test.

If the trial is successful, what would be the next steps?

We would seek NICE approval so that the test could become part of the routine pathway for investigating thyroid lumps in the UK. We will keep the BTF updated on our progress.

We are very grateful to Professor Hernan Gonzalez of GeneProdx, who invented ThyroidPrint, and Biocartis, which has made the test accessible through its technology. 

First issued: January 2025. Updated April 2026