GP Monitoring and Doctor Ordered Blood Tests

Regular blood testing can be an important part of managing an existing health condition or checking that a prescribed treatment is working as expected. Our GP monitoring blood tests offer a convenient way to check selected health markers privately, without waiting for a GP referral.  

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Underactive Thyroid Levothyroxine Monitoring Blood Test

Experience the convenience of monitoring your thyroid health from home with this simple thyroid blood test

  • Results estimated in 3 working days
  • 2 biomarkers
£35.00
Young woman with long blonde hair is smiling and looking at the camera.
“This collection means you can have the right test at the right time to ensure you can provide your specialist with all the information they need at any appointment to help make the correct decisions for your care.”

Dr Susanna Hayter, Digital Clinician, Medichecks

When might you need a thyroid monitoring blood test?

You may be advised to have a levothyroxine monitoring blood test after starting treatment, following a dose change, or as part of your long-term thyroid care. 

It may also be worth discussing testing with your doctor if symptoms have returned or changed. These might include unusual tiredness, feeling cold, unexplained weight changes, constipation, difficulty concentrating, changes in mood, or heart palpitations. These symptoms aren’t specific to thyroid disease, however, and can have many other causes. 

It’s generally recommended to carry out TSH testing every three months for adults taking levothyroxine until their level has stabilised, followed by annual testing. However, your own monitoring schedule may differ depending on your clinician’s advice. 

FAQs

Can I get a blood test without a GP referral? 

You can order a private blood test without first obtaining a GP referral. However, private testing doesn’t replace medical care. Speak to your GP if you have new or worsening symptoms, need a diagnosis, or think your prescription may need changing.

What blood test is used to monitor levothyroxine?

TSH is the main blood marker routinely used to monitor levothyroxine treatment. FT4 may also be measured, particularly when symptoms continue, or more information about circulating thyroid hormone is needed. The Underactive Thyroid Levothyroxine Monitoring Blood Test includes both TSH and FT4.

How often should thyroid levels be checked when taking levothyroxine?

For adults with primary hypothyroidism, NICE recommends considering TSH testing every three months until levels are stable, followed by testing once a year. Testing may be required sooner after a dose change or if symptoms return. Always follow the schedule set by your GP or specialist.

How long after changing levothyroxine should I have a blood test?

Thyroid levels need time to respond after a dose change. NHS monitoring guidance recommends testing from around six weeks after starting levothyroxine or changing the dose, with further testing based on the results and your clinician’s advice.

Can I take levothyroxine before my blood test?

We advise that you can take levothyroxine as usual, either before or after collecting your sample. Other thyroid medicines may have different instructions, so check the test preparation guidance carefully and tell your doctor about relevant medication.

Does biotin affect thyroid blood test results?

Biotin supplements can interfere with some laboratory thyroid tests. We recommend stopping biotin for two days before this test, although you should discuss this with your doctor before stopping it if it has been prescribed.

Can this blood test diagnose an underactive thyroid?

The Underactive Thyroid Levothyroxine Monitoring Blood Test is intended for people who have an underactive thyroid and take levothyroxine. It helps monitor treatment but isn’t designed to diagnose thyroid disease.

Can I change my levothyroxine dose based on my results?

You shouldn’t adjust or stop levothyroxine without speaking to the clinician responsible for your treatment. Your dose needs to be considered alongside your results, symptoms, medical history, and other factors.

Can I share private blood test results with my GP?

Your results can be shared with your GP or thyroid specialist. Your GP will decide how to use your results within your ongoing care.

What happens if my TSH results are abnormal?

An abnormal TSH result can have several explanations, including a levothyroxine dose that needs reviewing, inconsistent medication use, interactions with other medicines or supplements, illness, or another thyroid-related issue. Don’t change your dose yourself; discuss the result with your usual clinician.