What's this test for?

This test is ideal if you're experiencing unexplained fluid buildup around your lungs (pleural effusion) and your doctor needs to understand the cause. It helps identify whether the fluid accumulation is due to immune system problems, infections, or inflammatory conditions affecting your chest. Many people need this test when they have breathing difficulties, chest pain, or persistent cough that may be related to fluid in the chest cavity.

What happens after I get my results?

You'll receive detailed doctor notes in simple language explaining what your Complement C3 levels in the pleural fluid mean for your immune system and what might be causing the fluid buildup. These notes include guidance on whether your results suggest infection, inflammation, or an immune-related condition, and what next steps to consider. You'll also get the standard lab report and can track changes over time if you need repeat testing to monitor treatment progress.

What's included in this test?

This test measures Complement Component C3 in pleural fluid. C3 is a crucial protein in your immune system that helps fight infections and clear damaged cells. Measuring it in pleural fluid helps doctors determine whether fluid buildup is caused by infections, autoimmune conditions, or other inflammatory processes, providing critical diagnostic information that can't be obtained from regular blood tests alone.

How should I prepare for this test?

This test requires a pleural fluid sample, which must be collected by your doctor through a procedure called thoracentesis. Your healthcare provider will give you specific instructions before the procedure, which may include avoiding certain medications. The actual fluid collection is performed in a medical setting, and you should arrange for someone to drive you home afterward as a precaution.

Who should consider getting this test?

This test is recommended for people who have been diagnosed with pleural effusion (fluid around the lungs) and need to determine the underlying cause. It's especially important if you have symptoms like shortness of breath, chest pain, or cough along with the fluid buildup, or if your doctor suspects an immune disorder, infection, or inflammatory condition may be responsible for your symptoms.

What symptoms indicate I may need this test?

Common symptoms that might lead to this test include persistent shortness of breath, sharp chest pain that worsens with breathing or coughing, dry cough, and difficulty breathing when lying down. You might also experience fever, fatigue, or weight loss if the pleural fluid is related to infection or inflammation. If imaging tests show fluid around your lungs, this test helps identify the specific cause.

What is Complement C3 and why does it matter?

Complement C3 is a protein that plays a central role in your immune system's ability to fight infections and remove damaged cells. When measured in pleural fluid, it helps distinguish between different causes of fluid buildup. Low levels often indicate immune-related conditions or severe infections, while higher levels may suggest certain types of inflammation, helping guide your doctor toward the right diagnosis and treatment.

What does low Complement C3 in pleural fluid mean?

Low C3 levels in pleural fluid often suggest that your immune system is actively working to fight infection or inflammation in the chest cavity. This can occur with conditions like rheumatoid arthritis affecting the lungs, lupus, bacterial infections, or tuberculosis. Low levels help your doctor narrow down the diagnosis and determine the most appropriate treatment approach for your specific condition.

What does high Complement C3 in pleural fluid mean?

Elevated C3 levels in pleural fluid can indicate certain types of inflammation or that the fluid buildup is not primarily immune-related. This pattern may be seen with some infections, malignancies, or inflammatory conditions. Your doctor will interpret these results alongside other tests and your clinical symptoms to determine the exact cause and best treatment plan.

What happens if my results are abnormal?

Abnormal C3 levels help your doctor identify the underlying cause of your pleural effusion and guide treatment. Depending on results, you may need additional tests like imaging, cultures, or other fluid analyses. Treatment varies widely based on the cause and might include antibiotics for infections, medications for autoimmune conditions, or procedures to drain fluid and relieve symptoms. Your healthcare provider will create a personalized treatment plan based on your complete diagnostic picture.

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.

Pleural Fluid C3 Test - Lung & Immune Health 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

[email protected]

Pleural Fluid Test for Breathing Problems and Chest Pain

Complement Component C3, Pleural Fluid

90 day happiness guarantee

Prescription & fees included

Easy to understand results

Fast & convenient

90 day happiness guarantee

Prescription & fees included

Easy to understand results

Fast & convenient

What's this test for?

How should I prepare for this test?

What's included in this test?

Here’s why 1,000,000+ customers chose us for affordable hassle-free private blood testing.

Pleural Fluid Test for Breathing Problems and Chest Pain

90 day happiness guarantee

Prescription & fees included

Easy to understand results

Fast & convenient

1,000,000+ blood tests later, here's what our customers say