Bacterial Infection Blood Test

What is Bacterial Infections?

Bacterial infections occur when harmful bacteria invade the body and multiply, affecting various organs and systems. They are caused by pathogenic bacteria such as Staphylococcus aureus, Streptococcus species, Escherichia coli, and other bacterial organisms that trigger immune system activation. The Complement Component C3c and C4c test is the most important test for assessing immune response during bacterial infections because it measures complement system activation.

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What causes bacterial infections?

Bacterial infections are caused by pathogenic bacteria entering the body through cuts, contaminated food or water, respiratory droplets, or sexual contact. Common bacterial culprits include Staphylococcus aureus (causing skin infections and pneumonia), Streptococcus species (causing strep throat and skin infections), Escherichia coli (causing urinary tract and gastrointestinal infections), Salmonella (causing food poisoning), and Mycobacterium tuberculosis (causing tuberculosis). These bacteria multiply rapidly once inside the body, releasing toxins and triggering an immune response that leads to inflammation, fever, and other symptoms depending on which organ system is affected.

What is the best test for bacterial infections?

The Complement Component C3c and C4c test is the most important blood test for assessing immune response during bacterial infections because it measures how actively your immune system is fighting the infection. This test detects elevation in complement proteins, particularly C3c, which rise as part of the body's defense mechanism against bacterial invaders. The Complement Component C3c test alone can also measure immune system activity, while the ANA Screen IFA test helps identify current or past bacterial infections by detecting antibodies. These blood tests work alongside bacterial cultures and antigen detection tests to give a complete picture of infection status and immune response.

When should I get tested for bacterial infections?

You should get tested if you experience persistent fever above 101°F, signs of infection like redness, swelling, warmth, or pus at a wound site, unexplained fatigue lasting more than a few days, or symptoms like persistent cough, painful urination, or severe diarrhea. Testing is especially important if you have a weakened immune system, diabetes, or other chronic conditions that make you more vulnerable to infections. Get tested promptly if symptoms worsen rapidly or you develop confusion, difficulty breathing, or severe pain, as these may indicate a serious bacterial infection requiring immediate treatment.

What are the symptoms of bacterial infections?
Bacterial infections produce symptoms that vary depending on the affected area but commonly include fever, chills, fatigue, and general malaise. Skin infections cause redness, swelling, warmth, pain, and pus-filled bumps or wounds. Respiratory infections lead to cough, chest pain, difficulty breathing, and colored mucus. Urinary tract infections cause painful, frequent urination, cloudy or bloody urine, and lower abdominal pain. Gastrointestinal infections produce diarrhea, abdominal cramping, nausea, and vomiting. Some bacterial infections cause swollen lymph nodes, night sweats, or unexplained weight loss, especially when the infection becomes chronic or systemic.
Who is at risk for bacterial infections?
People with weakened immune systems face the highest risk, including those with HIV/AIDS, cancer patients undergoing chemotherapy, organ transplant recipients taking immunosuppressants, and individuals with diabetes or autoimmune diseases. Healthcare workers and people in close-contact environments like dormitories or military barracks have increased exposure to bacterial pathogens. Other risk factors include recent surgery or hospitalization, indwelling medical devices like catheters, poor nutrition, chronic alcohol use, smoking, advanced age, and infancy. People with chronic skin conditions, those who inject drugs, and individuals with poor hygiene practices also face elevated infection risk.
What happens if bacterial infections are left untreated?
Untreated bacterial infections can spread from the initial site to the bloodstream, causing sepsis—a life-threatening condition where the body's overwhelming immune response damages multiple organ systems. Localized infections can progress to abscesses, tissue death, or permanent organ damage depending on the affected area. Kidney infections can lead to kidney failure, while untreated heart valve infections (endocarditis) can cause heart failure or stroke. Some bacterial infections become chronic, causing ongoing symptoms and complications for months or years. In severe cases, untreated bacterial infections can result in shock, respiratory failure, amputation, or death, making prompt diagnosis and treatment essential.
Can bacterial infections be diagnosed with a blood test?
Blood tests play a crucial role in diagnosing bacterial infections by measuring immune system response and detecting bacteria in the bloodstream. The Complement Component C3c and C4c tests reveal immune system activation by measuring complement proteins that increase during infection. Blood cultures identify bacteria circulating in the bloodstream, while complete blood counts show elevated white blood cells fighting infection. C-reactive protein and erythrocyte sedimentation rate tests detect inflammation levels. However, blood tests work best when combined with other diagnostic methods like bacterial cultures from infected sites, urine tests, imaging studies, or physical examination findings to confirm the specific bacterial cause and guide appropriate antibiotic treatment.
How are bacterial infections treated?
Bacterial infections are treated primarily with antibiotics that kill bacteria or stop their growth, with the specific antibiotic chosen based on the type of bacteria and infection location. Common antibiotics include penicillins, cephalosporins, fluoroquinolones, and macrolides, typically taken for 7-14 days depending on infection severity. Severe infections may require intravenous antibiotics in a hospital setting. Treatment also includes supportive care like rest, hydration, fever reducers, and pain relievers to manage symptoms. Abscesses may need surgical drainage, while infected wounds require cleaning and dressing changes. Completing the full antibiotic course is essential even when symptoms improve, as stopping early can lead to antibiotic resistance and infection recurrence.
How can I prevent bacterial infections?
Preventing bacterial infections starts with thorough handwashing with soap and water for at least 20 seconds, especially before eating, after using the bathroom, and after touching potentially contaminated surfaces. Keep wounds clean and covered with sterile bandages, and avoid touching your face with unwashed hands. Practice safe food handling by cooking meat thoroughly, washing produce, refrigerating foods promptly, and avoiding cross-contamination. Stay up-to-date with vaccinations that prevent certain bacterial infections like tetanus, pertussis, and pneumococcal disease. Avoid sharing personal items like razors, towels, or eating utensils. Practice safe sex using condoms, maintain good oral hygiene, and strengthen your immune system through adequate sleep, nutritious diet, regular exercise, and stress management.
What natural remedies help with bacterial infections?
While antibiotics remain the primary treatment for bacterial infections, certain natural approaches support immune function and symptom relief. Consume immune-boosting foods rich in vitamin C (citrus fruits, berries), zinc (nuts, seeds, legumes), and probiotics (yogurt, kefir, fermented foods) to support your body's defenses. Garlic contains allicin with natural antibacterial properties, while raw honey and ginger have anti-inflammatory effects. Stay well-hydrated with water, herbal teas, and broths to help flush out toxins. Get adequate rest to allow your immune system to work effectively. Apply warm compresses to localized skin infections to reduce pain and promote drainage. However, natural remedies should complement, not replace, medical treatment—always consult a healthcare provider for proper diagnosis and antibiotic therapy when needed.
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Long story short:
  1. In the test options, use the filters or search box to narrow your choices and find the test you want.
  2. 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.
  3. 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.
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  6. 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.
  7. You’ll get your results via email & SMS and dive into understanding your body better. Yup, that easy!
  8. 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.
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.
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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.
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Complement Component C3c and C4c
Google reviews 505 reviews
$228 $178
What's included
Fast & easy, results by email & SMS
No need to visit a doctor
Private & confidential
No insurance needed
Results explained
No extra fees paid at the lab

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