C7 Complement Test
Short Name: C7 Complement
Also known as: Complement C7 Test, C7 Level Test, C7 Blood Test, Seventh Complement Component Test
C7 Complement Test test available at DNA Labs India for ₹12,000. Uses Radial Immunodiffusion on Serum samples. Results in Samples should be submitted by the 7th of the month. Reports are typically available after 2–3 weeks via the online portal, email, or WhatsApp.. Free home collection in 300+ cities across India.
🩺 Medically Reviewed By
Dr Pasupathy Arumugam
Consultant Pathologist · Reg: 21521
Last reviewed: September 7, 2026
Overview
The C7 complement test is performed to evaluate the functional integrity of the terminal complement pathway. It helps clinicians diagnose inherited or acquired C7 deficiencies, investigate the cause of recurrent Neisseria infections, monitor complement activity in autoimmune conditions such as systemic lupus erythematosus (SLE), and assess overall immune function in patients with unexplained immunodeficiency. The test is also used in pre-transplant immunological evaluations and in research settings studying complement-mediated diseases.
- Test Code
- 237
- CPT Code
- 86160
- ICD Code
- D84.1
- Price
- ₹12,000
- Sample Type
- Serum
- Result Time
- Samples should be submitted by the 7th of the month. Reports are typically available after 2–3 weeks via the online portal, email, or WhatsApp.
- Fasting Required
- No
- Method
- Radial Immunodiffusion
Sample Collection
A duly filled Test Send Out Consent Form (Form 35) is mandatory. Inform your doctor about all medications and supplements you are currently taking. No fasting is required unless specifically instructed by your physician.
Method: Venipuncture
Laboratory Analysis
A trained phlebotomist will collect approximately 2 mL of blood from a vein in your arm using standard venipuncture technique. The procedure typically takes less than five minutes.
Report Delivery
Apply pressure to the puncture site with a cotton ball for 3–5 minutes. Mild bruising may occur and usually resolves within a few days. You may resume normal activities immediately after sample collection.
Timeline: Samples should be submitted by the 7th of the month. Reports are typically available after 2–3 weeks via the online portal, email, or WhatsApp.
Patient Instructions
About This Test
Who Should Get This Test
The C7 complement test is performed to evaluate the functional integrity of the terminal complement pathway. It helps clinicians diagnose inherited or acquired C7 deficiencies, investigate the cause of recurrent Neisseria infections, monitor complement activity in autoimmune conditions such as systemic lupus erythematosus (SLE), and assess overall immune function in patients with unexplained immunodeficiency. The test is also used in pre-transplant immunological evaluations and in research settings studying complement-mediated diseases.
How to Prepare
- Duly filled Test Send Out Consent Form (Form 35) must accompany the sample
- Collect 2 mL (0.5 mL minimum) serum in an SST tube
- Ship the sample refrigerated (2–8 °C) or frozen (≤ −20 °C)
- Ensure the sample reaches the reference laboratory by the 7th of the month
- Avoid severe haemolysis or lipemia during collection
Doctor's Notes
Reviewed by Dr Pasupathy Arumugam — MBBS, MD (Pathology) · Reg. No. 21521
"The C7 complement test is a specialised investigation used when a deficiency of the terminal complement pathway is suspected. Low C7 levels can impair the formation of the membrane attack complex (MAC), leaving patients vulnerable to recurrent Neisseria infections. If you experience repeated episodes of meningococcal disease or unexplained immunodeficiency, discuss this test with your immunologist. Early detection allows timely prophylactic measures such as vaccinations and antibiotic prophylaxis."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Sample received without the mandatory Test Send Out Consent Form (Form 35)
- Haemolysed, lipemic, or grossly contaminated sample
- Sample received at room temperature beyond 6 hours of collection
- Insufficient sample volume (less than 0.5 mL serum)
- Unlabelled or mislabelled sample tube
Understanding Your Results
Normal C7 levels suggest that the terminal complement pathway is intact. This does not completely rule out complement dysfunction, and clinical correlation is essential.
Decreased C7 levels may indicate an inherited C7 deficiency, complement consumption due to active immune complex disease, or an acquired deficiency. Patients may be at increased risk of recurrent Neisseria infections.
Complete absence of C7 is strongly suggestive of a homozygous genetic deficiency. Genetic counselling and family screening are recommended. Prophylactic meningococcal vaccination should be discussed with the treating physician.
Consult your immunologist or treating physician if your C7 complement levels are outside the normal reference range, if you experience recurrent episodes of meningococcal infection, persistent unexplained fevers, or if there is a known family history of complement deficiency. Early intervention can help prevent life-threatening infections.
Limitations
- ⚠Results are not standalone; they must be interpreted alongside clinical findings and other complement component levels
- ⚠Radial immunodiffusion has a longer turnaround time compared to nephelometric methods
- ⚠The test does not measure the functional activity of C7, only its antigenic concentration
- ⚠Single-point measurements may not reflect dynamic changes in complement activation
Risks & Considerations
- ●Minor bruising or swelling at the venipuncture site
- ●Slight pain or discomfort during blood draw
- ●Rarely, lightheadedness or fainting during collection
Interfering Factors
- ●Recent complement-consuming infections may temporarily lower C7 levels
- ●Immunosuppressive medications such as corticosteroids may affect results
- ●Severe lipemia or haemolysis in the sample may interfere with analysis
- ●Recent blood transfusion may alter complement protein concentrations
Compare With Similar Tests
| Test | C7 Complement Test | C3 Complement Test | C4 Complement Test | CH50 (Total Complement) Test |
|---|---|---|---|---|
| Comparison | C7 Complement Test |
Frequently Asked Questions
What is the C7 complement test?
Why is the C7 complement test ordered?
What is the normal range for C7 complement levels?
What does a low C7 level indicate?
Is fasting required for the C7 complement test?
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How much does the C7 complement test cost in India?
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Can C7 deficiency be treated?
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