C1 Esterase Inhibitor
Private C1 Esterase Inhibitor blood test in London for £149.99, measuring one complement regulator with results in around 1 week.
Turnaround time
1 week
Biomarkers count
1
Book your test
Choose Service Type
Professional phlebotomist comes to you
+ £{{ home_visit_fee }}
Visit our clinic for your test
{{ clinic_visit_fee > 0 ? '+ £' + clinic_visit_fee : 'Free' }}
Home Visit Details
Home visits require at least 24 hours notice.
Select a clinic: Sorting by distance…
{{ clinicAddress(clinic) }}
{{ clinicAddress(selectedClinic) }}
Select a date
Select an hour
Available time slots: {{ timeSlots.length}}
Overview of the C1 Esterase Inhibitor
The C1 Esterase Inhibitor blood test measures C1 esterase inhibitor, commonly abbreviated to C1-INH, a protein that regulates several inflammatory pathways including the classical complement system.
C1-INH helps prevent uncontrolled activation of complement and other enzyme pathways that influence blood-vessel permeability.
When the amount or function of C1-INH is significantly reduced, excessive bradykinin can be generated, causing fluid to leak into tissues and produce episodes of angioedema.
The test contains 1 biomarker: C1 Esterase Inhibitor.
C1-INH testing is particularly important when hereditary angioedema is being investigated.
Hereditary angioedema can cause recurrent episodes of swelling affecting the face, lips, hands, feet, gastrointestinal tract and, potentially, the upper airway.
Unlike typical histamine-mediated allergic swelling, hereditary angioedema commonly occurs without hives and often responds poorly to antihistamines, corticosteroids or adrenaline.
Acquired C1 inhibitor deficiency can produce a similar pattern and may develop later in life in association with selected autoimmune or lymphoproliferative conditions.
C1 esterase inhibitor measurement is usually interpreted alongside C4 Complement, and functional C1-INH testing may be required where the amount of protein is normal but its activity is reduced.
What Does the C1 Esterase Inhibitor Test Check?
This test measures 1 biomarker.
C1 Esterase Inhibitor
Measures the concentration of C1-INH, a protein that regulates complement and bradykinin-related inflammatory pathways. Reduced levels can occur in hereditary or acquired C1 inhibitor deficiency associated with recurrent non-allergic angioedema.
Who May Benefit From the C1 Esterase Inhibitor Test?
This test may be suitable for people experiencing recurrent unexplained angioedema, particularly where swelling occurs without hives or has not responded as expected to conventional allergy treatment.
Recurrent facial swelling - Unexplained episodes involving the lips, eyelids or face may warrant complement investigation.
Recurrent swelling without hives - Bradykinin-mediated angioedema frequently occurs without the urticaria seen in many allergic reactions.
Episodes of tongue or throat swelling - Upper-airway involvement is an important feature of hereditary angioedema and can be life-threatening.
Recurrent severe abdominal pain with normal investigations - Swelling of the intestinal wall can cause episodic abdominal symptoms.
Poor response to antihistamines - C1-INH-related angioedema is mediated by bradykinin rather than histamine and often does not respond to standard allergy medication.
Family history of hereditary angioedema - Inherited C1 inhibitor deficiency can affect multiple members of the same family.
Low C4 Complement result - Persistently reduced C4 can prompt further investigation of C1-INH.
Angioedema beginning later in life - Acquired C1 inhibitor deficiency can occur in adults without a family history.
Specialist-requested complement testing - The test can be arranged privately where an immunologist, allergist, haematologist or GP has specifically requested C1-INH.
How to Prepare
Do not provoke an angioedema episode in an attempt to obtain an abnormal result.
Where hereditary angioedema remains strongly suspected despite a normal C1-INH concentration, functional C1 inhibitor testing and specialist immunology assessment may still be required.
Symptoms and Reasons to Consider the C1 Esterase Inhibitor Test
You may wish to consider the C1 Esterase Inhibitor test where recurrent swelling suggests a non-histamine-mediated form of angioedema.
Recurrent lip or facial swelling - Episodes may develop gradually and last longer than typical allergic swelling.
Swelling of the hands or feet - Peripheral swelling can occur without itching or urticaria.
Tongue swelling - Tongue involvement can threaten the airway and requires urgent assessment during an active episode.
Throat swelling or voice changes - Laryngeal angioedema is potentially life-threatening.
Recurrent severe abdominal pain - Intestinal angioedema can cause intense cramping, nausea and vomiting.
Swelling without an itchy rash - Absence of urticaria increases suspicion of bradykinin-mediated angioedema in the appropriate clinical setting.
Poor response to antihistamines or steroids - This pattern may differentiate C1-INH-related disease from conventional allergy.
Family history of similar swelling episodes - A family pattern can support investigation of hereditary angioedema.
C1-INH-related angioedema can involve the airway.
Active tongue or throat swelling, breathing difficulty, stridor, significant voice change or rapidly progressing facial swelling requires emergency medical assessment regardless of previous test results.
A normal C1-INH concentration does not completely exclude hereditary angioedema because some people have normal protein levels but reduced functional activity.
How to Book Your C1 Esterase Inhibitor Test
Booking your C1 Esterase Inhibitor test with London Blood Tests is straightforward.
Choose the C1 Esterase Inhibitor
Select the C1 Esterase Inhibitor test online and review the included complement-regulation biomarker before booking.
Select your sample collection option
Choose an in-clinic blood draw (+£35) or a home or hotel phlebotomy visit (+£60).
Attend your appointment
A trained professional will collect the required venous blood sample.
Laboratory analysis
Your sample is sent for specialist measurement of C1 esterase inhibitor.
Receive your results securely
Your result is sent securely by email, ready to review with a GP, immunologist, allergist or other suitably qualified healthcare professional.
When Will I Receive My Results?
The expected turnaround time for the C1 Esterase Inhibitor test is approximately 1 week after your sample arrives at the laboratory.
Specialist complement testing and laboratory authorisation are completed before results are released.
Additional functional testing, where required separately, may take longer.
Understanding Your Results
A reduced C1 esterase inhibitor concentration can support investigation of C1-INH deficiency.
In hereditary angioedema type I, the amount of C1 inhibitor is typically reduced.
In hereditary angioedema type II, the concentration can be normal or elevated but functional activity is reduced.
This means a normal quantitative C1-INH result does not completely exclude hereditary angioedema.
Acquired C1 inhibitor deficiency can also produce low concentrations and may be considered particularly when symptoms begin later in life without a family history.
C4 is frequently reduced in C1-INH deficiency and is commonly measured alongside C1 inhibitor.
Results should therefore be interpreted together with C4, functional C1-INH testing where appropriate, age at symptom onset and family history.
Why Book With London Blood Tests?
Private C1 Esterase Inhibitor testing in London - Access specialist complement investigation through London Blood Tests.
Relevant to hereditary angioedema investigation - C1-INH is a central marker when recurrent bradykinin-mediated swelling is suspected.
Useful alongside C4 Complement - The combined pattern can provide important supporting information.
Relevant to acquired angioedema assessment - C1-INH deficiency can occasionally develop later in life.
Targeted complement testing - Measure C1 Esterase Inhibitor without booking a broad autoimmune panel.
Specialist laboratory analysis - Your sample is processed using dedicated complement testing.
Clinic and home visit options - Choose an in-clinic blood draw or home or hotel phlebotomy.
Secure results by email - Receive your authorised result securely.
Clear pricing before booking - The C1 Esterase Inhibitor test is priced at £149.99, with sample collection charges shown separately.
Private C1 Esterase Inhibitor Blood Test in London
London Blood Tests provides the C1 Esterase Inhibitor blood test in London for people requiring specialist investigation of recurrent angioedema.
The test costs £149.99 and measures one biomarker: C1 Esterase Inhibitor.
Testing is particularly relevant where recurrent swelling occurs without hives, where attacks respond poorly to antihistamines or where there is a family history of hereditary angioedema.
Clinic and home or hotel phlebotomy options are available depending on location.
Results are generally interpreted alongside C4 and, where indicated, functional C1 inhibitor testing.