Complement C2
The Complement C2 test measures a key protein of the immune complement system. It helps assess immune defence and investigate rare complement deficiencies.
Turnaround time
5 business days
Biomarkers count
1
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Overview of the Complement C2
The Complement C2 blood test measures Complement Component 2, a protein involved in both the classical and lectin complement pathways.
The test contains 1 biomarker: Complement C2.
The complement system helps recognise microorganisms, regulate inflammation and remove immune complexes.
Within the classical pathway, activation of C1 leads to cleavage of C4 and C2, helping form an enzyme complex needed for downstream complement activation.
Inherited C2 deficiency is one of the more frequently recognised deficiencies of the classical complement pathway, although it remains uncommon overall.
Some people with C2 deficiency remain clinically well.
Others can have increased susceptibility to bacterial infections or autoimmune disease.
Low C2 can also occur because of acquired complement consumption rather than inherited deficiency.
For this reason, an abnormal result should generally be interpreted alongside C1q, C3, C4 and functional complement testing.
What Does the Complement C2 Test Check?
This test measures 1 biomarker.
Complement C2
Measures Complement Component 2, a protein involved in classical and lectin complement activation and normal immune defence.
Who May Benefit From the Complement C2 Test?
Complement C2 testing is usually used within specialist immune-system investigation.
People with recurrent bacterial infections - Complement deficiency can increase susceptibility to selected infections.
People with suspected inherited complement deficiency - C2 testing can identify a specific component abnormality.
People with an abnormal functional complement test - Individual component testing may help identify the affected protein.
People with unexplained low complement markers - Measuring C2 can help clarify the pattern.
People with early autoimmune disease - Classical complement deficiencies can be associated with lupus-like autoimmunity.
People with a family history of complement deficiency - Targeted testing may be appropriate.
People with a previous low C2 result - Repeat testing can help determine whether the abnormality persists.
People specifically referred for detailed immunology testing - C2 is generally most useful when interpreted with other complement investigations.
How to Prepare
Symptoms and Reasons to Consider the Complement C2 Test
C2 deficiency does not have one unique symptom. Testing may be considered when the pattern suggests an underlying complement-system abnormality.
Frequent bacterial respiratory infections - Recurrent infection may prompt investigation of immune defence.
Repeated severe infections - Unusual frequency or severity can justify specialist immunological assessment.
Delayed or recurrent infections despite appropriate treatment - Persistent infection patterns can sometimes indicate immune dysfunction.
Early-onset autoimmune disease - Classical complement deficiencies can increase autoimmune susceptibility.
Lupus-like symptoms at a young age - Complement deficiency may be considered as one part of specialist evaluation.
Previously low complement measurements - Additional C2 testing can help identify which component is abnormal.
A family history of complement deficiency - Inherited abnormalities can run in families.
Recurrent infections have many more common causes than C2 deficiency.
An abnormal C2 result should be interpreted by considering the complete immune history and other complement measurements.
How to Book Your Complement C2 Test
Booking your Complement C2 test with London Blood Tests is straightforward.
Choose the Complement C2
Select the individual Complement C2 test.
Select your sample collection option
Choose an in-clinic blood draw or professional home or hotel phlebotomy.
Attend your appointment
A trained professional collects the required venous blood sample.
Laboratory analysis
Your specimen undergoes specialist Complement C2 measurement.
Receive your results securely
Your authorised result is delivered securely.
When Will I Receive My Results?
The current turnaround is approximately 5 days after laboratory receipt.
Understanding Your Results
A reduced C2 concentration can result from inherited deficiency or acquired complement consumption.
One low result cannot automatically distinguish between the two.
Persistent marked reduction together with an abnormal classical complement functional assay may increase suspicion of inherited deficiency.
A normal result does not exclude abnormalities of other complement components.
The result should therefore be interpreted alongside C1q, C3, C4 and functional assays where appropriate.
Why Book With London Blood Tests?
Private Complement C2 testing in London - Access specialist complement-component testing privately.
Relevant to inherited complement deficiency - C2 deficiency can affect infection and autoimmune risk.
Useful after abnormal complement screening - Individual testing can help clarify the affected pathway.
Relevant to recurrent infection assessment - Complement testing may contribute to selected immunodeficiency investigations.
Specialist immunology analysis - Samples undergo dedicated laboratory testing.
Useful alongside C1q, C3 and C4 - Combined results provide more context.
Secure reporting - Receive your authorised result securely.
Clear pricing - Complement C2 costs £224.
Private Complement C2 Blood Test in London
London Blood Tests provides private Complement C2 testing in London for people requiring specialist complement-system assessment.
The test costs £224 and measures one biomarker: Complement C2.
Results are expected approximately 5 days after laboratory receipt.