What's this test for?

This test is ideal if you're experiencing unexplained inflammation, joint pain, skin rashes, or symptoms that suggest your immune system may be overactive. It's often used to help understand ongoing immune activity that other standard tests might miss. Many people use it alongside other immune markers when investigating autoimmune-type symptoms.

What's included in this test?

This test measures a single specialized marker that reflects recent activity of your immune system's complement pathway. Because this pathway gets switched on during inflammation, checking this marker can pick up on immune activation even when other common blood markers look normal. It's a targeted way to catch inflammatory activity that broader panels sometimes miss.

What happens after I get my results?

Your results will appear in your account with the normal range clearly explained next to your value. If your level is elevated, simple next steps include reducing inflammatory triggers in your diet, managing stress, and considering a retest in a few weeks to see if the pattern continues; if a value looks dangerously high, seek medical care promptly. You can download the standard lab report directly from your account at any time. The trends feature also lets you track this marker over time to see how it changes.

How can I naturally support a balanced immune response?

Eating an anti-inflammatory diet rich in vegetables, fatty fish, and healthy fats can help calm an overactive immune system. Getting consistent sleep and managing stress through activities like walking or meditation also supports healthy immune regulation. Limiting processed foods, alcohol, and smoking can reduce unnecessary inflammatory triggers in your body.

When will I get my results?

Results are typically ready within about 7 days of your lab visit. You'll get a notification once they're posted to your account, where you can view and download the full report.

Who should consider this test?

People with ongoing unexplained inflammation, recurring rashes, joint swelling, or other signs of immune system overactivity may want to consider this test. It's also useful for those already tracking an inflammatory condition who want another data point on immune activity. If you've had normal standard bloodwork but still have symptoms, this more specialized marker may offer additional insight.

What symptoms indicate I may need this test?

Common symptoms include unexplained skin rashes or hives, joint pain or swelling, fatigue that doesn't improve with rest, and recurring bouts of inflammation without a clear cause. Some people also notice symptoms that flare and then settle down repeatedly. If these patterns sound familiar, this test can help capture immune activity happening at that time.

What does a high result mean?

A high result means your immune system's complement pathway has been recently active, which usually points to ongoing inflammation somewhere in your body. This can happen even when other common inflammation markers appear normal. Simple next steps include noting any recent symptoms, reducing inflammatory triggers, and retesting to see if the level comes back down over time.

What causes elevated levels of this marker?

Elevated levels are usually caused by conditions that activate your immune system's complement pathway, such as autoimmune flare-ups, infections, or other sources of inflammation in the body. Physical stress, certain illnesses, and tissue injury can also temporarily raise this marker. Because levels can rise even when other tests look normal, it's a sensitive way to catch recent immune activation.

How often should I retest?

If your result is elevated, retesting in 4-6 weeks can help you see whether the inflammatory activity is settling down or continuing. If you're tracking a known condition, your retest schedule may depend on how often your symptoms change. Using the trends feature in your account makes it easy to compare results over time.

Getting your blood test with us is easy, private & backed by the power of science.Long story short: In the test options, use the filters or search box to narrow your choices and find the test you want. If you need a hand navigating through options, text our super friendly support team at 754-799-7833, and we'll provide tailored suggestions to help you find the ideal test. Once your order is placed, we’ll create your doctor’s lab order remotely, without any need for you to make a trip to a doctor in person or to talk to the doctor. Expect to receive your doctor’s lab order right in your inbox. It will also be in your patient portal if you need to find it later. We’ll also include instructions regarding fasting and other requirements for your test. Your patient portal will be auto-created hassle-free during checkout. If this is your first time ordering, you'll be prompted to create a password for instant login access to your patient portal. It's a quick way to conveniently access your orders and results whenever you want. When you’re ready, visit one of our 4,000 locations. Just bring your ID – no printing or faxing of your lab order is needed, as your order and details will already be in the lab system. Note that most lab locations don’t accept walk-ins, so it’s best to book an appointment in advance. Don’t worry – we’ll provide detailed instructions along the way. You’ll get your results via email & SMS and dive into understanding your body better. Yup, that easy! If you have any questions, please text us at 754-799-7833 or email support@privatemdlabs.com and we'll gladly help you.

How do I know which test to get?

In the test options, find the test you want. If you’re not sure which test to get, we can lend a hand in finding the right option. Just text or call us at 754-799-7833, email us at support@privatemdlabs.com, and we'll gladly help you. We've got your back and reply quickly.

When will my lab results be available?

Most test results will be available within 1–3 business days. Once they're ready, we'll send an email and text message to let you know. After your blood draw, just hang tight and don't worry – we'll keep you updated and in the loop! If you have any further questions, please text us at 754-799-7833 or email support@privatemdlabs.com, and we'll gladly help you.

Is it possible to make changes to my lab order if I made a mistake with the name, date of birth, or any other details?

Absolutely! We totally understand that errors can happen. No worries, we're here to help you. Just reach out to us via text at 754-799-7833 or shoot us an email at support@privatemdlabs.com. Remember to include your order number and let us know the correct information you’d like to update. Our awesome team will jump right in and make sure everything is sorted out and accurate for you. There are no changes necessary if your address is wrong on the requisition though. We don’t mail anything out. Our lab requires an address to be listed to generate an order.

Do you accept health insurance?

Only HSA & FSA is accepted. Our services are strictly self-pay and cannot be submitted to your health insurance provider except for Health Savings Accounts or Flexible Savings Accounts. This policy applies to all insurance companies, including federal health insurance programs like Medicare. If you have any questions, please text us at 754-799-7833 or email support@privatemdlabs.com.

Can I cancel my order?

Yes. We get it – sometimes your needs change. As long as your samples haven’t been collected yet, we’re happy to help you cancel your order. If you have any further questions, please text us at 754-799-7833 or email support@privatemdlabs.com. You can read more about our cancellation policy here.

How can I find a lab location near me?

During the ordering process, you’ll be able to select a specific lab near you, with no strings attached! You can switch it up later easily and visit any of our authorized locations as long as it’s the same lab company you selected your test for (Quest Diagnostics or Labcorp). Before you proceed with your order, feel free to browse through all our lab locations here. This will give you the peace of mind of knowing that there's a lab nearby your home, office or your favorite gym. If you have any questions, please text us at 754-799-7833 or email support@privatemdlabs.com and we'll gladly help you.

C4a Complement Test - Immune Inflammation Check

Getting your blood test with us is easy, private & backed by the power of science.

Long story short:

In the test options, use the filters or search box to narrow your choices and find the test you want.
If you need a hand navigating through options, text our super friendly support team at 754-799-7833, and we'll provide tailored suggestions to help you find the ideal test.
Once your order is placed, we’ll create your doctor’s lab order remotely, without any need for you to make a trip to a doctor in person or to talk to the doctor. Expect to receive your doctor’s lab order right in your inbox. It will also be in your patient portal if you need to find it later. We’ll also include instructions regarding fasting and other requirements for your test. Your patient portal will be auto-created hassle-free during checkout.
If this is your first time ordering, you'll be prompted to create a password for instant login access to your patient portal. It's a quick way to conveniently access your orders and results whenever you want.
When you’re ready, visit one of our 4,000 locations. Just bring your ID – no printing or faxing of your lab order is needed, as your order and details will already be in the lab system.
Note that most lab locations don’t accept walk-ins, so it’s best to book an appointment in advance. Don’t worry – we’ll provide detailed instructions along the way.
You’ll get your results via email & SMS and dive into understanding your body better. Yup, that easy!

754-799-7833

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