Test ID: SB-640 | Sample Type: Dried Blood Spot + Saliva | Technology: LC-MS/MS | Results Time: 3-5 Working Days After Laboratory Receives Sample | Laboratory: ZRT Laboratory - CLIA Certified | Hormone Specialist Doctor Interpretation: Included | Suitable For: Adults and Children | Collect Sample At Home: No Clinic Visit Required
What Does This Test Measure?
Blood Spot - Full Thyroid Panel: TSH, Free T3, Free T4, Total T4, TPO Antibodies, Thyroglobulin Antibodies.
Saliva - 4-Point Cortisol Profile: Morning, Noon, Evening, and Night Cortisol.
10 markers total - assessing thyroid function, autoimmune thyroid activity, and the full daily cortisol rhythm in a single at-home kit.
Related Symptoms
Persistent fatigue, unexplained weight gain, brain fog, low mood, anxiety, cold intolerance, dry skin, hair thinning, irregular or heavy periods, fertility difficulties, insomnia, night waking, chronic stress, burnout, or perimenopausal symptoms that are difficult to attribute to a single cause.
Who Should Consider This Test?
- Persistent fatigue or exhaustion that does not improve with rest or sleep
- Unexplained weight gain or difficulty losing weight despite diet and exercise
- Brain fog, poor concentration, or low mood
- Cold intolerance, dry skin, or hair thinning
- Irregular or heavy periods, or fertility difficulties
- Insomnia, night waking, or unrefreshing sleep
- Chronic stress or burnout
- Anxiety or emotional volatility
- Perimenopausal or menopausal symptoms difficult to attribute to a single cause
- Previously told thyroid results are normal but symptoms persist
- On levothyroxine or HRT and wanting comprehensive thyroid and cortisol monitoring
- Diagnosed or suspected Hashimoto's thyroiditis or autoimmune thyroid disease
Why This Test Is Particularly Important for Women
- Women are 5-10 times more likely than men to develop thyroid disorders - yet thyroid disease is frequently misattributed to stress, depression, or perimenopause
- Chronic cortisol elevation suppresses T4-to-T3 conversion, producing hypothyroid symptoms with a completely normal TSH - a pattern only detectable when Free T3 is measured alongside TSH and cortisol together
- Hashimoto's thyroiditis is present in women for years before TSH becomes abnormal - early detection requires direct TPO and Tg antibody testing
- The 4-point cortisol profile identifies which phase of the day is driving thyroid T3 suppression - morning, noon, evening, or night - enabling targeted intervention that a single cortisol value cannot provide
- HRT and the contraceptive pill alter thyroid hormone binding and metabolism - making FT3, FT4, and antibody testing alongside cortisol essential for women on hormonal treatment
Not Sure Which Test Is Right for You?
Email us at info@hormonelab.co.uk with your gender, age, symptoms, medications, and any current treatments. We will forward your enquiry to our doctors and respond within 24 hours.
How It Works
- Order your kit - delivered directly to your door
- Collect your blood spot via finger-prick and saliva at four time points across the day (morning before 9am, noon, evening, night)
- Post your samples to ZRT Laboratory using the return instructions provided
- Receive your full report by email within 3-5 working days
What You Receive
- All 10 marker results with sex- and age-appropriate reference ranges
- Visual charts for your cortisol daily curve and full thyroid panel
- Written interpretation by a Hormone Specialist PhD Doctor
- Personalised next-step recommendations
- 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) and saliva hormone testing
- Advanced LC-MS/MS technology for clinical-grade accuracy
- Qualified for the CDC Hormone Standardization (HoSt) Program
- 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
Why test thyroid and cortisol together?
Chronic cortisol elevation suppresses T4-to-T3 conversion, producing hypothyroid symptoms with a normal TSH. Testing both allows accurate differentiation between true thyroid disease, cortisol-driven thyroid suppression, and autoimmune thyroid conditions - each requiring a different approach.
Can I use this test if I am on levothyroxine, HRT, or the contraceptive pill?
Yes. These medications affect thyroid hormone binding and metabolism, which is precisely why testing FT3, FT4, and antibodies alongside TSH and cortisol provides a more complete picture. Follow the timing guidance in your kit.
How accurate is the cortisol measurement?
Saliva cortisol is measured using LC-MS/MS - the gold standard for bioavailable hormone measurement. It reflects the free, active fraction of cortisol rather than total bound cortisol measured in blood.
When should I collect my morning saliva sample?
Morning cortisol must be collected before 9am, ideally within 30 minutes of waking, to accurately capture the Cortisol Awakening Response.
Does the price include the laboratory fee?
Yes. The full laboratory analysis fee is included. There are no additional charges. You are only responsible for posting your samples to the laboratory.
How long is the kit valid for?
The kit must be used within 12 months of the purchase date.
