Test ID: BU-744 | Blood Spot + Dried Urine | Results in 3–5 Working Days
Could Iodine Deficiency Be Affecting Your Thyroid, Energy, or Metabolism?
Iodine is essential for the production of thyroid hormones. Without enough of it, your thyroid cannot function properly — leading to fatigue, weight gain, brain fog, and poor sleep. Yet iodine deficiency often goes undetected because it is rarely included in standard NHS blood tests.
This at-home test measures both your thyroid function and your iodine levels together, giving you a complete picture of how these two systems interact and where imbalances may be occurring.
What This Test Measures
Dried Blood Spot — Thyroid Panel:
- TSH (Thyroid Stimulating Hormone) — the master signal controlling your thyroid output
- Free T3 (FT3) — the active thyroid hormone that drives energy and metabolism at a cellular level
- Free T4 (FT4) — the storage hormone converted into T3; low levels indicate reduced thyroid output
- Total T4 (TT4) — total circulating T4, providing a broader view of thyroid hormone production
- TPO Antibodies (TPOab) — detects autoimmune thyroid activity, a key marker for Hashimoto's thyroiditis
- Thyroglobulin Antibodies (TgAb) — a second autoimmune marker, often elevated in both Hashimoto's and Graves' disease
Dried Urine — Iodine Panel:
- Iodine (I) — measured via ICP-MS technology; the most accurate method for assessing iodine status
- Creatinine (Crtn) — used to adjust iodine results for urine concentration, ensuring accuracy
Who Is This Test For?
This test is suitable for women, men, adults, and children who are experiencing any of the following:
- Persistent fatigue or low energy with no clear cause
- Unexplained weight gain or difficulty losing weight
- Brain fog, poor concentration, or memory lapses
- Poor sleep, low mood, or feelings of depression
- Cold intolerance or feeling cold when others do not
- Hair loss, dry skin, or slow reflexes
- A known or suspected thyroid condition such as hypothyroidism or Hashimoto's
- Concerns about iodine deficiency due to diet (especially low dairy or seafood intake)
- Those monitoring thyroid function without frequent GP visits
How It Works
- Order your kit — delivered directly to your door
- Collect your samples at home — a simple finger-prick for the blood spot and a brief urine collection; no clinic or GP visit required
- Post your samples to the laboratory using the prepaid instructions provided
- Receive your results by email within 3–5 working days of the lab receiving your samples
What You Receive With Your Results
- All markers displayed in clear graphics and easy-to-read values
- A written interpretation by a Hormone Specialist PhD Doctor
- Guidance on what your results mean and recommended next steps
- Laboratory fee included — no hidden charges
Why We Use ZRT Laboratory
All testing is performed by ZRT Laboratory — a globally recognised, CLIA-certified diagnostic laboratory founded in 1998 by Dr. David Zava, PhD. ZRT has performed over 11 million tests and is trusted by healthcare professionals in 96+ countries.
- Pioneers of at-home dried blood spot (DBS) hormone testing
- Advanced LC-MS/MS and ICP-MS technology for clinical-grade accuracy
- Qualified for the CDC Hormone Standardization (HoSt) Program for testosterone and estradiol
- Personalised reference ranges based on age and sex
Through our partnership with ZRT Laboratory, Hormone Lab UK delivers internationally recognised, research-backed hormone testing to people across the UK and Europe — from the comfort of home.
Frequently Asked Questions
What is the difference between this test and a standard thyroid blood test?
Standard NHS thyroid tests typically measure TSH only. This panel measures six thyroid markers — including Free T3, Free T4, and both thyroid antibodies — plus iodine levels via urine. This gives a far more comprehensive view of thyroid health and its nutritional root causes, which a standard test would miss.
Why is iodine tested through urine and not blood?
Urinary iodine is the internationally recommended method for assessing iodine status. Because the kidneys excrete excess iodine, urine reflects your overall intake and body stores more accurately than a blood sample. We use ICP-MS technology — the most precise measurement method available.
Can iodine deficiency cause thyroid problems?
Yes. Iodine is a key building block of thyroid hormones T3 and T4. Without sufficient iodine, the thyroid cannot produce adequate hormones, which can lead to hypothyroidism, an enlarged thyroid (goitre), fatigue, and metabolic slowdown. This test identifies whether iodine deficiency may be contributing to your symptoms.
What are TPO and thyroglobulin antibodies, and why do they matter?
These are autoimmune markers. Elevated TPO antibodies are the primary indicator of Hashimoto's thyroiditis — the most common cause of an underactive thyroid. Thyroglobulin antibodies (TgAb) are also elevated in autoimmune thyroid disease. Detecting these early allows you to take action before significant thyroid damage occurs.
Is this test suitable for children?
Yes. The test is suitable for adults and children. Sample collection is straightforward and non-invasive — the dried blood spot requires only a small finger-prick, and the urine collection is simple. If you are testing a child, please follow the collection instructions carefully.
How do I collect the samples?
Your kit includes full step-by-step instructions. The dried blood spot is collected via a gentle finger-prick device (lancet). The dried urine sample is collected by applying a small amount of urine to the test card using a pipette. Both samples are then air-dried and posted to the laboratory in the envelope provided.
When will I receive my results?
Results are typically available within 3–5 working days of the laboratory receiving your samples. You will receive your full report by email, including clear graphics, numerical values, and specialist commentary.
Is the laboratory fee included in the price?
Yes. The purchase price includes the full laboratory analysis fee. There are no additional charges. You are only responsible for posting your sample to the laboratory.
How long is the kit valid for?
The kit must be used within 12 months of the purchase date.
Can I take this test if I am already on thyroid medication?
Yes. This test can be taken while on thyroid medication and is particularly useful for monitoring your levels and understanding whether your current treatment is effective. Please note your current medication when reviewing your results.
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