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Your test arrives in discreet packaging with clear instructions.
About this test
Measures free thyroxine (FT4), the unbound fraction of a main thyroid hormone. It is usually interpreted with TSH and relevant medicines, symptoms and pregnancy status.
At a glance
- Sample: Blood
- Collection: Self-collected sample using the supplied kit
- Estimated turnaround: 1 day from laboratory receipt of a usable sample
What this test measures
- Free T4
- The unbound fraction of a main thyroid hormone. A low or high result is interpreted with TSH to assess thyroid function; illness, pregnancy and medicines can alter the pattern.
How clinicians use this test
Clinicians use Free T4 to assess the thyroid hormone pattern and help investigate possible underactive or overactive thyroid function. Diagnosis depends on the combination of results, symptoms, medicines and biological context.
Is this the right test for you?
An adult exploring the stated hormone marker with a clinician or monitoring an established plan, with collection timing and medicines taken into account.
Preparation and collection
Return the sample on the same day it is collected. Do not post over weekends or bank holidays.
Understanding your result
The laboratory will report Free T4 with an assay-specific reference range, threshold or qualitative interpretation. Read the biomarker explanation above for common reasons a result may be high, low, detected or reactive, then use the laboratory comment and clinical context to decide whether repeat or follow-up testing is needed.
Your results and next steps
Review the result with collection timing, medicines and related hormones in mind. Do not start, stop or change prescribed hormone or thyroid treatment from a single home-test result without clinician advice.
Limitations
Hormone values can vary with collection time, age, medicines and biological state. A single result does not establish the cause of symptoms.
When to get medical help
Do not wait for a home-test result if you feel seriously unwell. Call 999 for a life-threatening emergency, or use NHS 111 when you need urgent advice and are unsure what to do.
Who this test is for
- People who want a clearer view of the concern described above
- Anyone comfortable using the stated sample-collection method
- People who want doctor-reviewed results and practical next-step guidance
How it works
Collect your sample
Follow the kit guidance for the sample type shown above.
Post the same day
Post Monday–Thursday using the supplied tracked return.
Get your results
View secure, doctor-reviewed results and clear guidance online.
How to prepare
- Read the instructions before collecting your sample
- Check whether timing, fasting or medication guidance applies
- Collect and post on the same day wherever possible
Understanding your results
Clear ranges and doctor guidance
Your secure report shows the measured values, reference ranges and a doctor’s comment where appropriate.
Questions, answered
How accurate is an at-home test?
Your sample is processed by a professional UK partner laboratory using the same analytical methods used for clinician-requested testing. Sample quality depends on following the collection instructions carefully.
Are my results private?
Yes. Kits use discreet packaging and your results are delivered through a secure digital service.
Does this diagnose a condition?
No. The test checks and measures biomarkers. Results and the doctor’s comment can help you decide what to discuss with your GP.
When should I post my sample?
Collect and post on the same day, ideally Monday–Thursday, to avoid a sample waiting in the postal system over a weekend.
What happens if my sample cannot be processed?
The support team will explain the next step if the laboratory cannot process your sample. Any recollection or refund depends on the circumstances and the applicable policy.
When should I speak to my GP?
Speak to your GP if symptoms persist, worsen or concern you. Seek urgent medical help for severe or sudden symptoms.
Independent customer reviews
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2,423 customer reviews on Trustpilot
Read reviews on TrustpilotFree T4 Test£72.00