Persistent tiredness, unexplained weight changes, feeling unusually cold or hot, or changes in heart rate can sometimes occur with thyroid problems. However, these symptoms also have many other possible causes, and symptoms alone cannot confirm a thyroid disorder.

This article explains how underactive and overactive thyroid conditions differ, what thyroid blood tests check, and when speaking with a GP may be appropriate.

Key Takeaways

• Thyroid problems can involve too little or too much thyroid hormone
• Symptoms vary and overlap with many other health conditions
• TSH is commonly used as an initial thyroid blood test
• T4, T3 or thyroid antibodies may be added depending on the clinical situation
• Persistent symptoms, abnormal results or a neck lump should be discussed with a GP

What Are Thyroid Problems?

The thyroid is a small gland at the base of the neck. It produces hormones that help regulate metabolism, heart rate, body temperature and weight. When the thyroid produces too little or too much hormone, a range of symptoms can develop that affect many different body systems.

Healthdirect Australia provides a useful overview of thyroid problems and common symptoms, noting that conditions can involve either insufficient or excessive thyroid hormone production.

What Are the Symptoms of an Underactive vs Overactive Thyroid?

Underactive and overactive thyroid conditions can produce different symptom patterns, although symptoms vary between individuals. Understanding the difference helps clarify which direction a GP may consider when reviewing your symptoms.

Having one or several of these symptoms does not confirm a thyroid disorder. Similar symptoms can occur with iron deficiency, perimenopause, sleep problems, stress, medication effects and many other conditions. A GP considers the overall clinical picture rather than individual symptoms in isolation.

What Blood Tests Check Thyroid Function?

Thyroid assessment commonly starts with a blood test measuring thyroid-stimulating hormone, or TSH. Depending on the result and clinical situation, free T4, T3 or other tests may also be requested.

TSH

The pituitary gland makes TSH and signals the thyroid to produce hormones. A high or low TSH result can provide useful clues about thyroid function, but the result needs to be interpreted alongside other clinical information.

Free T4 and T3

Free T4 is one of the main thyroid hormones. T3 may be particularly relevant when an overactive thyroid is suspected. Results are interpreted together rather than in isolation, as each provides a different piece of the picture.

Thyroid Antibodies

Specific thyroid antibody tests may be requested when an autoimmune thyroid condition such as Hashimoto’s disease or Graves’ disease is suspected. The type of antibody test depends on the clinical question, and antibody testing is not required with every thyroid function test.

Does an Abnormal TSH Result Mean You Have a Thyroid Problem?

Not always. A high or low TSH result provides useful information. Still, your GP may need to consider free T4 or T3, symptoms, medicines, recent illness and other clinical factors before determining what the result means.

The RACGP notes that mild TSH abnormalities can sometimes be transient, and repeat testing may be appropriate before treatment decisions are made depending on the clinical context. 

A single abnormal TSH result does not always provide the complete picture. Your GP may consider other thyroid hormone levels, symptoms, medicines and whether repeat testing or further investigation is appropriate. 

When Might Thyroid Ultrasound or Other Tests Be Needed?

A GP may consider additional investigation where there is:

• A palpable lump or visible neck swelling
• A goitre identified on examination
• Diagnostic uncertainty despite blood results
• Abnormal findings requiring further evaluation

Ultrasound is not routinely required simply because a thyroid blood test is abnormal. Healthdirect notes that imaging may be considered where nodules are identified, while RACGP guidance advises against routine ultrasound in uncomplicated hypothyroidism without a palpable nodule.

When Should You See a GP About Thyroid Symptoms?

Consider seeing a GP if you experience:

• Persistent fatigue without a clear explanation
• Persistent or unexplained weight gain or loss
• Ongoing heat or cold intolerance
• Recurring palpitations or tremor
• Persistent bowel or menstrual changes
• A lump or swelling in the neck
• A previous abnormal thyroid result that has not been followed up
• Pregnancy or pregnancy planning where thyroid concerns exist

If symptoms persist or several changes are occurring together, a general medicine consultation can help your GP assess the broader pattern and decide whether thyroid testing or another assessment may be appropriate.

What Happens at a GP Appointment for Possible Thyroid Problems? 

A GP may review:

• Your symptoms and how long they have been present
• Your personal and family medical history
• Medicines and supplements that may influence thyroid function
• Heart rate, blood pressure and neck examination where relevant
• Whether blood tests are appropriate at this stage
• Whether imaging, repeat testing or specialist referral may be needed

When thyroid tests are requested, Paterson Healthcare’s pathology collection service can collect referral-based blood samples on site. Thyroid function testing is among the blood tests that a GP may request.

To discuss persistent symptoms or a previous thyroid result, contact Paterson Healthcare to arrange a GP appointment.

FAQs

Can thyroid problems cause tiredness? 

Yes. Both underactive and overactive thyroid conditions can contribute to fatigue, but tiredness has many possible causes. Persistent fatigue should be assessed alongside your overall health history.

What is the first blood test used to check thyroid function? 

TSH is commonly used as the initial thyroid-function test. Depending on the result and clinical circumstances, your GP may also request free T4, T3 or other thyroid-related tests.

Does a high TSH always mean hypothyroidism?

No. A high TSH can suggest an underactive thyroid, but results need to be interpreted alongside other hormones, symptoms, medicines and individual clinical circumstances.

Can thyroid problems cause weight changes? 

An underactive thyroid may be associated with weight gain, while an overactive thyroid may contribute to weight loss. Weight changes also have many other possible causes and require full clinical assessment.

Should a GP check a thyroid lump? 

Yes. A lump or swelling in the neck should be clinically assessed. Depending on the findings, a GP may consider blood tests, imaging or specialist referral.

Resources and References

• Healthdirect Australia — Thyroid Problems https://www.healthdirect.gov.au/thyroid-problems
  
• Healthdirect Australia — Thyroid Function Tests https://www.healthdirect.gov.au/thyroid-function-tests
  
• RACGP — Thyroid Disease: Using Diagnostic Tools Effectively https://www1.racgp.org.au/ajgp/2021/january-february/thyroid-disease-using-diagnostic-tools-effectively
  
• Healthdirect Australia — Hypothyroidism https://www.healthdirect.gov.au/hypothyroidism