Blood Culture Test

Why am I having this test?

A blood culture test is done to see if you have an infection in your blood called septicemia. This type of infection is also called blood poisoning.

You may need this test if:

You have a fever, chills, nausea, or tiredness.
Your health care provider thinks you may have blood poisoning.

What is being tested?

Your sample will be tested for germs called bacteria or fungi.

What kind of sample is taken?

A person having a blood sample taken from the arm.

At least two blood samples are needed for this test. They're taken by putting a needle into a blood vessel. The samples should come from two different veins. Two samples are taken because:

There's a better chance of finding the infection.
There's a better chance of the results being right. Even if you clean well, there may be germs on your skin. These germs can cause a positive result. If this happens, you'll need to have the test again.

How do I prepare for this test?

Tell your provider if you're taking antibiotics.

If possible, blood samples should be taken before you start the medicine.
If blood cultures are done while you're on an antibiotic, the samples should be taken right before you take a dose of the medicine.

How are the results reported?

Your results will be reported as positive or negative. For this test, a normal finding is a negative result.

What do the results mean?

A negative result means you don't have blood poisoning.
A positive result means you may have blood poisoning. It may also mean you have a serious infection.

Talk with your provider about what your results mean. In some cases, your provider may do more testing to confirm the results.

Questions to ask your health care provider

Ask your provider or the department doing the test:

When will my results be ready?
How will I get my results?
What are my treatment options?
What other tests do I need?
What are my next steps?

This information is not intended to replace advice given to you by your health care provider. Make sure you discuss any questions you have with your health care provider.