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Selenium
68.00
This test measures selenium levels to assess antioxidant and thyroid support. Selenium is vital for immunity, metabolism, and cellular protection.
Turnaround time
6 days
Biomarkers count
1
Same-Day Appointments
UKAS Accredited Labs
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Under 18? Patients under 18 can only be seen at GB Medlabs and Clinilabs, Monday to Friday only.
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Details about Selenium
What is a Selenium test?
A selenium test measures the level of selenium in your blood, an essential trace mineral with powerful antioxidant properties. Selenium is required for the function of enzymes that protect cells from oxidative damage and plays a critical role in thyroid hormone metabolism.
Low selenium levels can affect immunity, thyroid function, fertility, and recovery from illness, often without obvious symptoms.
Why do I need a Selenium test?
Selenium deficiency is common in people with restrictive diets, digestive issues, thyroid problems, or chronic stress.
Reasons for testing include:
• Thyroid imbalance or autoimmune thyroid disease
• Persistent fatigue
• Weak immune system
• Hair thinning
• Fertility concerns
• Poor recovery from illness
• High oxidative stress
• Digestive or absorption issues
Benefits of the test
1. Supports thyroid hormone conversion (T4 to T3)
2. Assesses antioxidant protection
3. Evaluates immune system support
4. Detects hidden nutritional deficiency
5. Supports fertility and reproductive health
6. Useful in autoimmune thyroid conditions
7. Helps explain fatigue and low immunity
8. Guides precise supplementation
Expanded benefit explanation
Selenium is essential for thyroid enzymes and antioxidant defence. Identifying deficiency allows targeted support for thyroid, immunity, and overall metabolic health.
Step-by-step — How testing works
We offer two UK-wide testing options:
Clinic testing
• Choose nearest UK clinic
• Blood sample collected
• Laboratory analysis performed
• Results securely returned
Home visit (+£60)
• Phlebotomist visits you
• Blood sample collected safely
• Sample sent to lab
• Results delivered confidentially
Your results explained
Low levels
Typical UK reference range: 0.9–1.9 µmol/L
Low selenium may contribute to thyroid dysfunction, fatigue, and poor immunity.
Normal levels
Indicates adequate antioxidant and thyroid support.
High levels
High selenium is uncommon and usually related to excessive supplementation.
How It Works
Simple steps to get your results
1
Book Online
Choose your test online and book in seconds. Select your preferred clinic location or home visit option.
2
Visit or Test at Home
Attend one of our UK or London clinics, arrange a home nurse visit, or use a finger-prick kit where available.
3
Get Your Results
Your sample is analysed by accredited UK laboratories, with secure results delivered directly to you.
Take control of your health with London Blood Tests
WhatsApp UsHow to Prepare for Your Test
Follow these guidelines for accurate results
Sample Timing
Where possible, attend your blood test between 7am and 12pm. Please wait until any short-term illness or infection has fully resolved before testing. Avoid intense exercise for 24–48 hours beforehand, as this can affect certain markers.
Fasting & Hydration
Fasting is not always required, but some tests may recommend it. If fasting is advised, avoid food for 8–12 hours before your appointment and drink water only. Stay well hydrated, as this helps with sample collection and accuracy.
Medications & Supplements
Continue prescribed medications unless advised otherwise by your clinician. Avoid vitamin, mineral, or biotin supplements for at least 24–48 hours before your test, as these can interfere with results. If you are unsure about any medication or supplement, please let us know before your appointment.
Hormones & Menstrual Cycle
For hormone-related tests, timing within your menstrual cycle may be important. If relevant, follow any specific guidance provided on your test page.
If you have any questions or special circumstances, our team is happy to advise before your appointment.
Frequently Asked Questions
Yes, it is essential for thyroid hormone conversion.
Yes, through antioxidant and immune enzyme function.
Fasting is not usually required.
Yes, in some cases.
Avoid selenium supplements for 24 hours before testing.
Yes, soil content affects dietary selenium.
It can support thyroid enzyme function.
Yes, excess levels can be toxic.
If deficient, repeat after supplementation.
Yes, it supports reproductive health.
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