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Thyroid Peroxidase Antibodies
56.40
This blood test measures thyroid peroxidase antibodies linked to autoimmune thyroid disease. It helps identify immune-related thyroid dysfunction, even when hormone levels are normal.
Turnaround time
2 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 Thyroid Peroxidase Antibodies
What is the Thyroid Peroxidase Antibodies test?
The Thyroid Peroxidase Antibodies (TPOAb) test measures antibodies produced by the immune system against thyroid peroxidase, an enzyme essential for thyroid hormone production. When these antibodies are present, they interfere with normal thyroid function.
Elevated TPO antibodies are a key marker of autoimmune thyroid disease, particularly Hashimoto’s thyroiditis and, less commonly, Graves’ disease. Their presence indicates immune-mediated damage rather than a purely hormonal imbalance.
This test is commonly used alongside thyroid hormone tests to clarify the underlying cause of thyroid dysfunction.
Why do I need a Thyroid Peroxidase Antibodies test?
Autoimmune thyroid disease is a leading cause of underactive and fluctuating thyroid function. Antibodies may be present long before hormone levels become abnormal.
You may benefit from this test if you experience:
- Persistent fatigue or low energy
- Weight gain or difficulty losing weight
- Cold intolerance
- Hair thinning or hair loss
- Brain fog or low mood
- Irregular menstrual cycles or fertility concerns
- Family history of thyroid or autoimmune disease
- Borderline or changing thyroid hormone results
Identifying TPO antibodies helps distinguish autoimmune thyroid disease from other thyroid conditions and supports early intervention and monitoring.
Benefits of the test
- Detects autoimmune thyroid disease
Identifies immune-related thyroid dysfunction. - Explains symptoms with normal TSH
Antibodies may be present before hormone changes. - Supports early diagnosis
Detects thyroid autoimmunity at an early stage. - Clarifies cause of hypothyroidism
Helps confirm Hashimoto’s-related thyroid disease. - Useful for fertility and pregnancy planning
Thyroid autoimmunity can affect reproductive outcomes. - Supports long-term monitoring
Antibody levels help track disease activity. - Improves diagnostic confidence
Adds immune context to thyroid hormone testing. - Simple blood-based testing
Requires only a single blood sample.
Step-by-step: How we offer testing
Clinic-based testing (UK-wide)
- Choose your nearest UK clinic
- Attend your appointment
- A clinician draws a blood sample
- Sample is sent to the laboratory
- Results are issued once analysis is complete
Home or hotel visit (+£60, UK-wide)
- Book a mobile phlebotomist
- Blood sample taken at your home or hotel
- No need to attend a clinic
- Sample securely transported to the laboratory
Your results explained
Negative (no antibodies detected)
- Thyroid peroxidase antibodies not detected
- UK standard: Negative
- Suggests thyroid dysfunction is unlikely to be autoimmune
Mild to moderately elevated antibodies
- Antibody levels above reference range
- UK standard (typical): >35 IU/mL
- Indicates autoimmune thyroid activity
High antibody levels
- Markedly elevated TPO antibodies
- UK standard: Significantly above 35 IU/mL
- Common in Hashimoto’s thyroiditis and active autoimmune disease
Antibody levels should always be interpreted alongside thyroid hormone tests and symptoms.
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
They indicate immune system activity against the thyroid gland.
Yes, antibodies may appear before hormone levels change.
They can persist long-term but may fluctuate over time.
Not always; some individuals remain asymptomatic initially.
Yes, they are strongly associated with Hashimoto’s thyroiditis.
Yes, thyroid autoimmunity can influence reproductive health.
Yes, it helps assess autoimmune thyroid risk in pregnancy.
Stress may affect immune activity and antibody expression.
Monitoring may be helpful in certain clinical contexts.
It indicates autoimmune involvement of the thyroid and supports further endocrine evaluation.
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