Thrombin Time
The Thrombin Time test measures how quickly blood forms a clot after thrombin is added. It helps identify clotting abnormalities and fibrinogen-related disorders.
Turnaround time
Results available 1 day after arrival in lab. Doctor's report sent the day after results available (if required)
Biomarkers count
1
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Details about Thrombin Time
What is the Thrombin Time test?
The Thrombin Time (TT) test is a coagulation blood test that evaluates the final step of the clotting process—conversion of fibrinogen into fibrin. In the laboratory, thrombin is added to plasma and the time taken for a clot to form is measured.
Unlike other clotting tests, TT specifically reflects fibrinogen quantity and function and is highly sensitive to substances that interfere with fibrin formation, such as heparin. It is commonly used alongside other coagulation tests to investigate abnormal bleeding or clotting.
Why do I need a Thrombin Time test?
An abnormal Thrombin Time can indicate problems with fibrinogen or the presence of anticoagulants that affect clot formation. It is particularly helpful when other coagulation tests are abnormal or when bleeding risk needs clarification.
You may need this test if you have:
- Unexplained or excessive bleeding
- Easy bruising
- Prolonged bleeding after surgery or dental work
- Suspected fibrinogen deficiency or dysfunction
- Liver disease affecting clotting factors
- Suspected heparin contamination or exposure
- Abnormal results on other coagulation tests
The test helps narrow down the cause of clotting abnormalities and supports further haematological assessment.
Benefits of the test
- Assesses final clot formation step
Focuses specifically on fibrin formation. - Sensitive to fibrinogen disorders
Helps identify low or abnormal fibrinogen. - Detects anticoagulant interference
Highly sensitive to heparin and similar agents. - Supports bleeding disorder investigation
Useful when bleeding tendency is unexplained. - Complements other coagulation tests
Adds clarity alongside PT and APTT. - Simple and rapid analysis
Requires only a blood sample. - Useful in liver disease assessment
Liver dysfunction can affect fibrinogen levels. - Objective laboratory measurement
Provides clear, time-based results.
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
Shortened thrombin time (uncommon)
- Clot forms faster than expected
- UK standard: Below lab reference range (typically <14 seconds)
- May occur with elevated fibrinogen levels
Normal thrombin time
- Clot forms within expected time
- UK standard: Typically 14–21 seconds
- Suggests normal fibrinogen function
Prolonged thrombin time
- Delayed clot formation
- UK standard: >21 seconds
- May indicate low or abnormal fibrinogen, heparin presence, or inhibitors affecting clotting
How It Works
Simple steps to get your results
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Attend one of our UK or London clinics, arrange a home nurse visit, or use a finger-prick kit where available.
Get Your Results
Your sample is analysed by accredited UK laboratories, with secure results delivered directly to you.
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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.