Patient education: Blood culture (The Basics)

What is a blood culture? — This is a lab test that checks a sample of blood for bacteria and other germs.

An infection anywhere in the body can spread to the blood and travel through the whole body. This can cause a serious illness called "sepsis." If sepsis is not treated quickly, it can be life-threatening.

For a blood culture, a sample of your blood is sent to a lab. In the lab, they add a special substance that causes germs to grow. If there are germs in your blood, these will show up within a few days.

Why might I get a blood culture? — Your doctor might order a blood culture:

●If you have symptoms of sepsis – These can include fever, low body temperature, chills, fast breathing, or fast heartbeat. Severe sepsis can cause more serious symptoms. These might include confusion, trouble breathing, belly pain, or problems with the organs.

●If you have certain types of infection – Some infections are more likely than others to lead to sepsis. They include infections related to a device in the body, like a pacemaker or IV catheter. Other examples include infections in the heart, spine, or brain.

●To help decide what antibiotics to prescribe – A culture can show what kind of bacteria are causing an infection. This is important for deciding how to treat it.

●To check if antibiotics are working

A blood culture is most often done in the emergency department or the hospital. The staff will take a small amount of blood from a vein for testing.

What do my results mean?

●If your blood culture is "positive," this means that you do have bacteria or other germs in your blood. Your doctor or nurse will talk to you about what to do next. If you have a bacterial infection, your doctor will prescribe an antibiotic to treat it.

●If your blood culture is "negative," this means that you do not have bacteria or other germs in your blood. If you have symptoms but your blood culture is negative, your doctor might do other tests to try to figure out the cause.

More on this topic

Patient education: Sepsis in adults (The Basics)