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* This is not a home test kit. You will need to visit a local lab for testing.
Fasting Required: No
Turnaround Time: 2-10 business days
Specimen Type: Blood
C4, Complement Component 4
C4 is one of the nine numbered proteins in the body’s complement system. Complement proteins support and strengthen the immune system so your body can fight off viruses, bacteria, and other germs. Low levels of C4 can be a risk factor for autoimmune diseases or recurrent infections.
The C4 Complement Blood Test results measure the levels of this protein in your blood.
This test can help detect and diagnose diseases including systemic lupus erythematosus (SLE), a chronic inflammatory disorder affecting joints, nerves, heart, skin, eyes, and other areas of the body. Other diseases that may require testing include serum sickness and chronic active hepatitis.
The test doesn’t require any special preparations for the blood draw.
Normal C4 levels are different for men (12 to 72 mg/dL) and women (13 to 75 mg/dL). If C4 complement is high, that can indicate inflammation-based diseases such as cancer or ulcerative colitis. Low C4 complement levels, on the other hand, may be a sign of infection, malnutrition, or hepatitis.
Based on your results, you may want to do more testing. You can measure levels of other individual proteins, as with a C3 test, or check all of them with a Complement Total (CH50) Blood Test. If your doctor wants to diagnose a specific issue such as hepatitis or cancer, we also offer several liver function and cancer screening tests to check for those diseases.
These results can be used to guide your treatment plan, so you can make lifestyle modifications or start medication as needed. If you want help analyzing these results, schedule a telehealth visit with one of our board-certified physicians.
Take a blood test for C4 complement near you, thanks to our 4,000-plus Labcorp or Quest Diagnostic partner labs across the country. With this wide-ranging network and streamlined ordering process, it’s never been easier to take control of your health.
Here’s how simple it is to get a C4 complement blood test:
Step 1: Purchase the test online and print out the lab order. (Depending on the state where you live, you may not even need a physician’s approval to get the test.)
Step 2: Find the facility closest to you with our lab locator and schedule the blood test.
Step 3: Get your blood drawn (be sure to bring the lab order with you to your appointment).
Step 4: You can find the results in your confidential Personalabs portal, typically within 2 to 10 business days. (Contact us if you need a specific turnaround time and we will reach out to the lab on your behalf, as times can vary by location.)
Order your Personalabs test today!
Provider | LabCorp, Quest |
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Order Your Test
Create an account, choose your tests, checkout securely, generate your lab order
Generate & Print Out Lab Order
Our physician network will approve your order within 2-4hrs.
Visit the Lab
The test price decides which lab you will visit: Quest or Labcorp. Find a location in your area.
Get Your Results
Results can be provided in as little as 24-48 hrs. For more complex tests, please contact us for turn around times.
Based on 2,260 reviews subject to moderation
Easy to find my tests, order, sample, and prompt return of the reread more
Review of 4/19/2025, reflecting an experience on 4/14/2025 by Steven M
Good , but nothing listing what you’re charging for what differenread more
Review of 4/19/2025, reflecting an experience on 4/3/2025 by Rodnet J
The tech was extremely rough with me, physically hurt me and pushread more
Review of 4/19/2025, reflecting an experience on 4/2/2025 by Dominic Y
Great service provides easy access to routine wellness and other read more
Review of 4/19/2025, reflecting an experience on 4/10/2025 by Brian B
I don't like the fact that I have to have physician approval beforead more
Review of 4/19/2025, reflecting an experience on 4/4/2025 by Patricia S
Very good, I’m very glad with the Service
Review of 4/19/2025, reflecting an experience on 4/5/2025 by Lorena M
The only problem I have is with the self check-in kiosk. Besides read more
Review of 4/19/2025, reflecting an experience on 4/9/2025 by Dakota H
It’s quick, fast, easy, simple and most importantly discreet !
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A very receptive and friendly employeee.
Review of 4/4/2025, reflecting an experience on 3/31/2025 by Cory H
It was smooth process and easy
Review of 3/31/2025, reflecting an experience on 3/26/2025 by christian R
Very simple and easy to accomplish what you need. Easy schedulinread more
Review of 3/30/2025, reflecting an experience on 3/19/2025 by Ben C
I love how easy it is to order the specific lab tests you need toread more
Review of 3/30/2025, reflecting an experience on 3/18/2025 by Dawn Michelle S
I didn’t get the results i requested
Review of 3/30/2025, reflecting an experience on 3/13/2025 by Latina W
Very thankful for fast attention and the personnel were kind
Review of 3/15/2025, reflecting an experience on 3/12/2025 by Ana Maria W
Very customizable tests, approval from doctors within a couple horead more
Review of 3/13/2025, reflecting an experience on 3/10/2025 by Wassim E
Easy to find my tests, order, sample, and prompt return of the reread more
Review of 4/19/2025, reflecting an experience on 4/14/2025 by Steven M
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Very customizable tests, approval from doctors within a couple horead more
Review of 3/13/2025, reflecting an experience on 3/10/2025 by Wassim E