C4 Complement Test: Booking, Price, and Results
About C4 Complement Test: Booking, Price, and Results
| Field | Value |
|---|---|
| Also Known As | Complement Component 4, Serum C4, C4 Complement Blood Test, Complement Activity Test (C4) |
| Sample Type | Venous blood (serum) |
| Fasting Required | No fasting required |
| Report Time | Within 24 to 48 hours |
| Recommended For | All age groups, males and females |
| Price | Starting at ₹650 |
What Is a C4 Complement Test?
The C4 complement test is a blood test that measures the level of Complement Component 4, a protein that plays a key role in your immune system. Also called Serum C4 or the Complement Activity Test (C4), it helps doctors assess how well your immune system is functioning. A small blood sample drawn from a vein is used for the test. Doctors typically order it when they suspect an autoimmune condition or recurring infections.
What Does a C4 Complement Test Measure?
The test measures the amount of C4 protein circulating in your blood. C4 is one of nine core proteins in the complement system, a group of proteins that work alongside your immune system to fight bacteria and viruses, and to clear dead cells from the body. The table below summarises what is measured.
| Parameter | What It Reflects |
|---|---|
| Complement C4 protein | The amount of C4 in your blood shows how well your immune system’s complement pathway is working. |
Why Is a C4 Complement Test Done?
A doctor may order this test for several reasons, including investigating immune system problems or tracking the progress of a known condition.
Common Symptoms That May Require This Test
Your doctor may recommend a C4 complement blood test if you have any of the following symptoms:
- Skin rash (a butterfly rash) across your cheeks
- Fever
- Swollen lymph nodes
- Hearing loss
- Vision loss
- Hair loss
- Weight loss
- Mouth ulcers
- Headache
- Fatigue
- Pain in the chest
- Joint pain and swelling
Conditions This Test Can Help Detect
The complement component 4 test can help identify or evaluate a range of conditions, including:
- Systemic lupus erythematosus (SLE), an autoimmune disease where the immune system attacks healthy tissue
- Rheumatoid arthritis, a condition causing joint inflammation
- Early glomerulonephritis, which is inflammation of the kidney's filtering units
- Hereditary angioedema, an inherited condition that causes swelling under the skin
- Cryoglobulinaemia, a condition involving abnormal proteins in the blood
- Immune complex disease, cirrhosis of the liver, and certain kidney conditions
- Congenital C4 deficiency
- Monitor immune complex-related conditions, e.g. glomerulonephritis (GN)
- Recurrent bacterial infections
- Determine a treatment plan for an autoimmune disease
C4 Complement Test for Chronic Disease Monitoring
Doctors may repeat this test over time to check whether treatment for an autoimmune condition is working. In people with lupus, C4 levels transiently fall during a disease flare-up and return to the normal range once inflammation settles. For those with active autoimmune disease, testing every 3 to 6 months is common. Those with a stable condition may only need testing every 6 to 12 months.
How to Prepare and What to Expect
No special preparation is needed for this test. The process is straightforward and takes only a few minutes.
Do You Need to Fast?
No. Fasting is not required before a C4 complement test. You can eat and drink normally on the day of your appointment.
Practical Tips Before Your Test
A few simple steps can help ensure a smooth experience:
- Tell your doctor about all medications, supplements, or herbal products you are currently taking
- Drink plenty of water before your appointment, as good hydration makes the blood draw easier
- Wear a top with short or loose sleeves for easy access to your arms
- Let your doctor know about any recent infections or injuries, as these may influence your results
Step-by-Step Procedure
Here is what typically happens during a C4 complement blood test collection:
- A trained phlebotomist will ask you to sit comfortably and will select a suitable vein, usually in the inner elbow area.
- An elastic band is wrapped around your upper arm to make the vein more visible.
- The skin over the vein is cleaned with an antiseptic wipe.
- A small needle is gently inserted into the vein. You may feel a brief sting.
- A small amount of blood is collected into a labelled vial, and the elastic band is removed.
- The needle is withdrawn, and a bandage is placed over the site. The entire process usually takes under five minutes.
Factors That Can Affect Accuracy
Certain factors may affect the reliability of your result:
- Poor handling of the blood sample after collection can cause falsely low C4 readings
- High levels of fat in the blood (lipaemia) can interfere with the measurement
- Rheumatoid factors present in the blood may also affect the result
- Recent infections or ongoing inflammation can temporarily alter C4 levels
- Some medications may influence complement activity
Understanding Your C4 Complement Test Results
Your results show whether your C4 levels fall within, above, or below the accepted reference range. Always review your results with your doctor, who will consider them alongside your symptoms and medical history.
| Parameter | Low | Normal | High |
|---|---|---|---|
| Complement C4 (mg/dL) | Below 16 | 16 to 48 | Above 48 |
| Complement C4 (g/L) | Below 0.16 | 0.16 to 0.48 | Above 0.48 |
These ranges are general guidelines. Your doctor will interpret your results based on your age, health history, and other factors. Always consult a qualified healthcare professional for personalised medical advice.
Results During Special Conditions
Certain health conditions can affect how your C4 results should be read:
- People with hereditary angioedema almost always have permanently low C4 levels. During an active episode, C4 can fall below detectable limits due to rapid consumption by the complement system.
- In lupus, C4 levels drop during flare-ups and typically recover as inflammation subsides. This pattern helps doctors track disease activity over time.
- In rheumatoid arthritis, C4 may appear normal or high in blood, while being low in joint fluid. The site of testing matters in this condition.
How to Maintain Healthy Levels
These general tips can support immune and overall health:
- Follow your prescribed treatment plan if you are managing an autoimmune condition, and attend all follow-up appointments.
- Eat a balanced diet with enough protein, vitamins, and minerals to support normal immune function.
- Report any new or worsening symptoms, such as joint swelling, unexplained fatigue, or skin changes, to your doctor promptly.
Lupin Diagnostics C4 Complement Test Price and Home Collection
The C4 complement blood test starts at ₹650 and is available with convenient home sample collection through Lupin Diagnostics.
| City | Approximate Price (₹) |
|---|---|
| Coimbatore | ₹650 |
| Mumbai | ₹650 |
| Bengaluru | ₹650 |
| Chennai | ₹650 |
| Hyderabad | ₹650 |
| Kolkata | ₹650 |
| Pune | ₹650 |
| Guwahati | ₹650 |
How to Book
- Select the test on the Lupin Diagnostics website.
- Choose your city and preferred time slot.
- Opt for home sample collection by a certified phlebotomist, or visit your nearest Lupin Diagnostics centre.
- Receive your report via email or WhatsApp within the stipulated turnaround time.
Home Collection
Lupin Diagnostics offers home sample collection for the Serum C4 test across multiple cities in India. All samples are processed in NABL-accredited laboratories by trained technologists. Your digital report is delivered within 24 to 48 hours and can be accessed via email or WhatsApp.
Frequently Asked Questions
The test measures the amount of C4 protein in your blood to assess how well your complement immune system is working. Doctors use it to help investigate autoimmune conditions such as lupus, recurring infections, and certain kidney or liver disorders. It is also used to monitor how well the treatment is working over time.
No fasting is needed. You can eat and drink as usual before your appointment. No special preparation is required for the C4 complement test.
Yes. C3 and C4 are the most commonly ordered complement proteins and are often tested together. Measuring both gives your doctor a clearer picture of how the complement system is functioning and whether any specific part of the immune pathway is affected.
A low C4 result on its own may point to an inherited deficiency. When both C3 and C4 are low, it may suggest an autoimmune condition such as lupus. Low C4 is also associated with hereditary angioedema, haemolytic anaemia, and certain kidney conditions. Your doctor will consider your full clinical picture before drawing any conclusions.
The frequency depends on your health situation. If you have an active autoimmune disease, your doctor may recommend testing every 3 to 6 months. For a stable condition, testing every 6 to 12 months alongside routine follow-up is common. Your doctor will advise the appropriate schedule for you.
Yes. In lupus, C4 levels typically fall during a flare and rise again when the disease is under control. If your complement activity test (C4) results show rising levels while you are on treatment, it may indicate that your treatment plan is working effectively.
The blood draw is safe, and complications are uncommon. You may feel a brief sting when the needle is inserted, and slight bruising or soreness at the site is possible. These usually resolve on their own within a day or two.
C4 Complement Test: Booking, Price, and Results
