Also Known As: BC, Culture blood
What Is A Culture, Blood Test?
A blood culture test is performed to determine if you have any infection in your bloodstream that can affect your body systems in the long run. Many doctors analyze the sample of your blood for systemic infection caused by bacteria or yeast. Blood usually does not have any fungus or bacteria in it. This test can help find germs that can lead to lifelong health issues.
The presence of bacterial infection in the bloodstream is termed bacteremia. It can be a severe condition because your blood can travel to any part of the body and spread the bacteria on its way. It commonly affects your kidneys, lungs, heart, gallbladder, and gastrointestinal tract. You may also develop bladder infection if you have a weak immune system. This health condition commonly occurs in infants and older adults because of certain diseases like cancer or the constant use of medications involving chemotherapy and corticosteroids. These drugs can change how your body fights infection and make your immune system extremely fragile.
Your sample blood will be added to a substance that facilitates germ growth for this test. Your doctor might refer to some other additional tests to choose the right treatment regime against the infection.
What Is The Test Used For?
A blood culture test is often ordered when your doctor or health practitioner suspects a blood infection in your system. It becomes very important for you to get tested for that infection as it can lead to some serious complications if not managed in time. The most common complication of blood infection is sepsis, where the pathogens causing the infection in blood start interfering with your body's natural fortifications. It can prevent your immune system from working properly while producing harmful toxins to damage your organs. Your doctor can specify the bacteria or organism responsible for a blood infection and the best treatment options to combat it with the results.
This test is helpful for:
- Finding bacterial infections already sprayed into the bloodstream, including sepsis, kidney infection, meningitis, pneumonia, or osteomyelitis.
- To know which type of bacteria is causing the infection.
- To find a fungal infection caused by yeast within the blood.
- To check for endocarditis, infection of the heart valves.
- For finding the best antibiotics to eliminate the microorganisms, fungus, and bacteria causing blood infection.
- To know the causes of unexplained high fever or the reason behind your extreme illness.
Why And When Do You Need Culture, Blood Test?
If you are about to get this test done, the chances are that you might have a systemic infection, and your doctor wants to check for certain kinds of bacteria or fungus in the blood. The test results can help them develop the most promising treatment options for you. Your doctor will suggest this test if you are showing symptoms including:
- High-grade fever
- Fatigue and tiredness
- Nausea and vomiting
- Urinating less than normal
- Rapid breathing
- Uncontrollably fast heartbeat
- Muscle aches
- Mottled skin
If left untreated, your blood infection can advance to its severe stage called sepsis. The symptoms of sepsis include all those listed above and some other severe signs. With a more severe infection, your symptoms may also include:
- Formation of small blood clots in small blood vessels
- Inflammation in multiple areas of your body simultaneously
- Organ failure
- A severe drop in the blood pressure
What kind of sample is required for the test?
During the test, your health care provider or a lab assistant will use a needle to draw a blood sample, usually from the arm. They often collect blood from two or three different sites or a single site a few hours apart. In people with severe infections, a long-term catheter insertion is required in the major vein to keep receiving chemotherapy and other nutritional supplements during the treatment. Therefore, the blood for culture tests is collected from their catheters only for such individuals.
Do You Need To Prepare For The Test?
In general, there is nothing special that you can do before the test until your doctor advises you regarding anything specific. However, before giving the blood, it is essential to tell your doctor about your ongoing medications, especially about the consumption of any antibiotics in the past few days.
Are There Any Risks To This Test?
You can experience some complications with this test only after you give blood. But remember that blood draws are a routine procedure, and they can barely cause any severe side effects. During or after the procedure, you might experience:
- Excessive bleeding
- Fainting or feeling light-headed
- Bleeding under your skin is called a hematoma
- Any other new infection
What Do The Test Results Mean?
If your blood culture test result is positive, it indicates that you have a fungal or bacterial infection in the bloodstream that needs to be addressed and treated instantly. Septicemia or sepsis can be a life-threatening condition, especially for immunocompromised individuals. After the test, your doctor will start you on a broad-spectrum antibiotic while waiting for the test results to arrive.
In some cases, positive test results can also be falsely positive due to skin contamination or other factors. For example, suppose the two blood culture sets are positive simultaneously with the same bacteria. In that case, the organism present in the culture is the leading cause of your infection. However, if one set is positive and the other one is negative, it could mean an infection or contamination. When it happens, the doctor might suggest a re-test to evaluate your health status.
If the blood culture results are negative, you might not be going through sepsis caused by bacteria or yeast. But some bacteria or other microorganisms are quite challenging to grow in a culture, so further tests may be required. You can have all the symptoms of a blood infection because of a virus that doesn't grow in routine blood culture media and needs advanced laboratory tests for accurate diagnosis.
Frequently ordered together
Bacterial Culture Abscess
CBC (includes Differential and Platelets)
CBC Differential and Platelets with Smear Review
CBC includes Differential and Platelets with Pathologist Review
Culture Anaerobic Bacteria with Gram Stain
Culture, Yeast, with Identification
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