Infections Blood Test

What is Infections?

Infections occur when harmful microorganisms such as bacteria, viruses, fungi, or parasites invade the body and multiply. The body responds by producing measurable changes in white blood cells, antibodies, and immune system proteins. The Complete Blood Count (CBC) is the most important test for detecting infections because it measures white blood cell count and differential, which become elevated as the immune system mobilizes to fight pathogens.

RECOMMENDED TEST Complete Blood Count / CBC (includes Differential and Platelets)
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What causes infections?

Infections are caused by harmful microorganisms including bacteria like Streptococcus and Staphylococcus, viruses such as influenza and COVID-19, fungi like Candida, and parasites. These pathogens enter the body through various routes including breaks in the skin, inhalation, contaminated food or water, or direct contact with infected individuals. Once inside, they multiply and trigger an immune response that produces measurable changes in blood markers like white blood cells and antibodies.

What is the best test for infections?

The Complete Blood Count (CBC) with Differential is the most important test for detecting infections because it measures your white blood cell count and identifies which types of white blood cells are elevated. Bacterial infections typically cause neutrophils to increase, while viral infections often elevate lymphocytes. For chronic or past infections, the IgG test is essential as it measures immunoglobulin G antibodies that remain elevated after fighting long-term infections. The IgG, IgA Indirect Immunofluorescence test is the best choice when you need to identify specific pathogens, as it detects antibodies against particular infectious agents.

When should I get tested for infections?

You should get tested if you experience persistent fever above 100.4°F that lasts more than three days, unexplained fatigue and body aches, swollen lymph nodes in your neck or groin, or wounds that are not healing properly. Testing is also important if you have a weakened immune system due to conditions like diabetes or HIV, take immunosuppressive medications, or have recently traveled to areas with infectious disease outbreaks. Early detection through blood testing helps identify infections before they become severe and guides appropriate treatment.

What are the symptoms of infections?
Common symptoms of infections include fever, chills, sweating, fatigue, muscle aches, headaches, and loss of appetite. You might notice swollen lymph nodes, redness or warmth around a wound, coughing, sore throat, nasal congestion, nausea, vomiting, or diarrhea. The specific symptoms depend on the type and location of the infection, with respiratory infections causing breathing difficulties, urinary tract infections producing painful urination, and skin infections showing redness and pus formation.
Who is at risk for infections?
People with weakened immune systems are at highest risk, including those with HIV, cancer, diabetes, or autoimmune diseases. Older adults and young children have less robust immune defenses and are more vulnerable to infections. Those taking immunosuppressive medications like corticosteroids or chemotherapy drugs, healthcare workers exposed to pathogens, people living in crowded conditions, and individuals with poor nutrition or chronic stress also face increased infection risk.
What happens if infections are left untreated?
Untreated infections can spread from the initial site to other parts of the body through the bloodstream, causing sepsis, a life-threatening condition where the infection triggers widespread inflammation. Bacterial infections may lead to abscesses, organ damage, or chronic conditions like endocarditis affecting the heart. Some infections can cause permanent tissue damage, scarring, or loss of function in affected organs. In severe cases, untreated infections can result in septic shock, organ failure, and death.
Can infections be diagnosed with a blood test?
Yes, blood tests are essential tools for diagnosing infections by measuring your immune system's response. The Complete Blood Count reveals elevated white blood cell counts that indicate your body is fighting an infection, while the differential count helps distinguish between bacterial and viral causes. Antibody tests like IgG and IgA detect specific immune proteins produced in response to particular pathogens, confirming both active and past infections. Blood cultures can identify bacteria or fungi circulating in your bloodstream, and inflammatory markers like fibrinogen indicate ongoing infectious processes.
How are infections treated?
Treatment depends on the type of infection causing your symptoms. Bacterial infections are treated with antibiotics specific to the bacteria identified, while viral infections may require antiviral medications or supportive care to help your immune system fight the virus. Fungal infections need antifungal medications, and parasitic infections require antiparasitic drugs. Your doctor will prescribe treatment based on blood test results, the severity of symptoms, and the specific pathogen involved. Rest, hydration, and fever-reducing medications support recovery regardless of the infection type.
How can I prevent infections?
You can prevent infections by washing your hands frequently with soap and water for at least 20 seconds, especially before eating and after using the bathroom. Stay up to date with vaccinations for influenza, COVID-19, and other preventable diseases. Avoid close contact with people who are sick, cover your mouth and nose when coughing or sneezing, and avoid touching your face with unwashed hands. Maintain a healthy lifestyle with proper nutrition, adequate sleep, regular exercise, and stress management to keep your immune system strong.
What natural remedies help with infections?
Natural support for fighting infections includes getting adequate rest to allow your immune system to work effectively, staying well-hydrated with water and warm fluids like herbal tea, and consuming nutrient-rich foods high in vitamins C and D, zinc, and protein. Honey has natural antibacterial properties and can soothe throat infections, while garlic contains allicin with antimicrobial effects. Probiotics support gut health and immune function. However, natural remedies should complement, not replace, medical treatment, especially for serious infections that require antibiotics or antiviral medications.
How’s this work?
Getting your blood test with us is easy, private & backed by the power of science.

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.
  4. 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.
  5. 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.
  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.
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.
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* Regular blood test results (e.g., CBC) typically start arriving the next business day after sample collection. More complex tests, such as hormone panels, may take up to 10–15 business days due to their complexity.

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Complete Blood Count / CBC (includes Differential and Platelets)
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

Sample results

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