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Immunology & Serology Home collection available

C4 Complement

Parameters1 tested
SampleBlood
FastingNot required
Report inSame day

How to prepare

No fasting needed

You can eat and drink normally before the test.

Good to know

No special preparation needed.

Medicines

Tell our phlebotomist about any medicines you take. Don't stop them without asking your doctor.

Comfortable clothes

Wear a loose sleeve so the sample can be taken easily from your arm.

How it works

Book onlinePick a time slot
Home visitSealed, sterile kit
Lab testingBarcode tracked
ReportIn same day

About this test

C4 is a complement protein that helps antibodies destroy germs. It is often low in active lupus and in hereditary angioedema.

Why is this test done?

  • Monitor lupus
  • Check for hereditary angioedema
  • Look into kidney inflammation

Symptoms — when should you get tested?

  • Repeated swelling of face, lips or throat
  • Joint pain and rash
  • Swelling of feet

Normal range

Adults 10 – 40 mg/dL

Reference ranges differ slightly between labs, methods, age and sex. Always discuss your report with your doctor.

If your result is high

High C4 is usually seen with inflammation.

Common reasons
  • Infections
  • Inflammatory conditions

If your result is low

Low C4 suggests complement use or an inherited problem.

Common reasons
  • Active lupus
  • Hereditary angioedema
  • Cryoglobulinaemia

How is the test done?

  1. 1
    Book online

    Choose your slot for home collection or a visit to our centre.

  2. 2
    Blood sample taken

    A trained phlebotomist takes a small blood sample from a vein in your arm with a sealed, single-use needle. It takes about 2 minutes.

  3. 3
    Tested in our lab

    Your barcoded sample is tested on automated machines with strict quality checks.

  4. 4
    Report on WhatsApp

    A pathologist checks the result and the report reaches you on WhatsApp and email.

Frequently asked questions

No fasting is needed for this test. You can eat and drink normally.

Your report is usually ready in same day after the sample reaches our lab. We send it on WhatsApp and email, and you can also download it from the Reports page.

Please call our team to confirm whether home sample collection is available for your location and test.

This test needs a blood sample. No special preparation needed.

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