Understanding Your Thyroid Test Results: A Complete Guide
Confused by your thyroid test results? Learn what TSH, FT4, FT3, and antibodies mean, how to spot hypothyroidism or hyperthyroidism, and when to take action. Medimob Screenings offers accurate at-home thyroid testing with expert insights.
Your thyroid is a small but mighty gland that regulates metabolism, energy, mood, and even heart function. If you’ve ever had a thyroid function test (TFT), you may have been handed a report with terms like TSH, FT4, FT3, and thyroid antibodies—leaving you wondering what it all means.
At Medimob Screenings, we believe in empowering you with clear, accurate insights into your thyroid health. This guide will help you decode your test results, understand what’s normal (and what’s not), and know when to take action.
Why Thyroid Testing Matters
The thyroid produces two key hormones:
- T4 (thyroxine) – The inactive storage form
- T3 (triiodothyronine) – The active hormone that affects metabolism
These hormones are regulated by TSH (thyroid-stimulating hormone), released by the pituitary gland. When thyroid levels drop, TSH rises to stimulate production. When levels are too high, TSH falls to slow things down.
Thyroid dysfunction can lead to:
✔ Fatigue, weight changes, and mood swings
✔ Heart rhythm abnormalities
✔ Fertility issues and pregnancy complications
✔ Cognitive decline and depression
Because symptoms are often vague, blood tests are the only reliable way to diagnose thyroid disorders.
Key Thyroid Markers & What They Mean
| Marker | What It Measures | Normal Range (UK) | High/Low Implications |
|---|---|---|---|
| TSH | Thyroid-stimulating hormone | 0.4–4.0 mIU/L (varies by age) | High TSH = Hypothyroidism (underactive) Low TSH = Hyperthyroidism (overactive) |
| Free T4 (FT4) | Available thyroxine | 9–25 pmol/L | Low FT4 + High TSH = Hypothyroidism High FT4 + Low TSH = Hyperthyroidism |
| Free T3 (FT3) | Active thyroid hormone | 3.5–7.8 pmol/L | High FT3 = Hyperthyroidism (Often tested if TSH is low but FT4 is normal) |
| Thyroid Antibodies (TPO, TgAb, TRAb) | Autoimmune activity | Negative or low | Elevated = Hashimoto’s or Graves’ disease |
(Sources: NICE Guidelines, 2019; British Thyroid Foundation, 2023)
Interpreting Your Thyroid Test Results
1. Hypothyroidism (Underactive Thyroid)
- TSH > 4.0 mIU/L + Low FT4 = Overt hypothyroidism (needs treatment)
- TSH > 4.0 mIU/L + Normal FT4 = Subclinical hypothyroidism (may need monitoring)
- Common causes: Hashimoto’s disease, iodine deficiency, medication side effects
2. Hyperthyroidism (Overactive Thyroid)
- TSH < 0.4 mIU/L + High FT4/FT3 = Overt hyperthyroidism
- TSH < 0.4 mIU/L + Normal FT4/FT3 = Subclinical hyperthyroidism
- Common causes: Graves’ disease, thyroid nodules, thyroiditis
3. Autoimmune Thyroid Disease
- High TPO antibodies → Hashimoto’s (leads to hypothyroidism)
- High TRAb antibodies → Graves’ disease (leads to hyperthyroidism)
(Source: Journal of Clinical Endocrinology & Metabolism, 2023)
When Should You Get Tested?
Consider a thyroid test if you experience:
🔹 Unexplained fatigue or weight changes
🔹 Hair loss, dry skin, or brittle nails
🔹 Anxiety, depression, or brain fog
🔹 Irregular periods or fertility struggles
🔹 Heart palpitations or high cholesterol
High-risk groups:
- Women over 30 (5–8x more likely than men)
- Pregnant women (thyroid dysfunction increases miscarriage risk)
- People with a family history of thyroid disease
- Those with autoimmune conditions (e.g., type 1 diabetes, celiac disease)
(Source: American Thyroid Association, 2024)
How Medimob Screenings Can Help
We offer at-home thyroid blood tests that check:
✅ TSH, FT4, FT3 (essential for diagnosing dysfunction)
✅ Thyroid antibodies (detects autoimmune causes)
✅ Full lab analysis with clinician-reviewed results
Why test with us?
✔ UK-accredited lab analysis
✔ Personalised health insights
✔ Doctor-recommended next steps
Advanced Thyroid Screening Blood Test
References
- National Institute for Health and Care Excellence (NICE). (2019). Thyroid disease: assessment and management. [NG145].
- British Thyroid Foundation. (2023). Thyroid Function Tests.
- Jonklaas, J., et al. (2023). Guidelines for the Treatment of Hypothyroidism. Thyroid, 33(2), 167-186.
- American Thyroid Association. (2024). Thyroid Function Tests.