Skip to content
Trusted to do 100,000+ tests and consultations per month.
Trusted to do 100,000+ tests and consultations per month.

NOTES FROM THE LAB

Hello! My name is Jamila Quaye and I am a senior biomedical scientist with a specialism in haematology, here at One Day Tests laboratory.

Triiodothyronine (T3) - description and reference ranges

What is it?

Triiodothyronine (T3) is one of two main hormones that is produced by your thyroid. The other hormone is called Thyroxine (T4). Both T3 and T4 work to regulate your metabolism and affect your weight, temperature and nervous system, among others.

T3, T4 and TSH results are frequently used together for the diagnostics of thyroid problems.

Reference ranges

If your indicative T3 level is lower than the reference range for our laboratory:

Low T3 levels may mean you have hypothyroidism, a condition in which your body does not produce enough T3.

You should discuss this result with your GP.

If your indicative T3 level is higher than the reference range for our laboratory:

If your results show high T3 levels, it may mean you have a thyroid condition.

You should discuss this result with your GP.

QUICK TEST FINDER

Find what you need in under 30 seconds with our (very clever!) test finder.

We offer a huge range of markers all a few clicks away, as well as fastest turnaround times.

FIND YOUR TEST
QUICK TEST FINDER

YOU MAY ALSO LIKE TO READ

  • testing diabetes device
    Dr. Adam Staten

    WHAT ARE THE 20 WARNING SIGNS OF DIABETES?

    Diabetes often develops gradually, with early warning signs that can be subtle and easy to miss. Many symptoms overlap with everyday issues such as stress, dehydration, or tiredness, which is why diabetes frequently goes undiagnosed until blood sugar levels have been high for some time. Recognising these warning signs early can help prevent complications and support timely intervention.
    Read now
  • foods high in zinc
    Dr. Adam Staten

    What Are the 10 Signs of Low Zinc?

    Zinc is a trace mineral involved in immune function, wound healing, hormone balance, and hundreds of enzyme reactions throughout the body. Because it's needed in so many processes, low zinc levels can produce a wide and sometimes confusing range of symptoms. Below are 10 of the most common signs of low zinc.
    Read now
  • apolipoprotein blood vial
    Dr. Adam Staten

    WHAT HAPPENS WHEN APOLIPOPROTEIN B IS HIGH?

    If you have recently had a cholesterol or lipid panel done and seen the term apolipoprotein B, or ApoB, on your results, you might be wondering what it actually means for your health. It is a marker that is becoming more widely tested because it often reveals more than standard cholesterol numbers alone, but a high result on its own can feel confusing without context. This article explains what apolipoprotein B does in the body, what a raised level suggests, and what practical steps you can take if your result comes back high. If you would like to check your own levels, you can book an apolipoprotein B blood test through One Day Tests, with no GP referral needed and results usually available within a day or two.
    Read now