A blood culture is a test that checks for bacterial or fungal infection of the blood.
An infection in the blood can be very serious. This test can help your child’s healthcare provider know if your child’s blood is infected and identify the type of bacteria or fungus causing the infection. Knowing what kind of bacteria or fungus is causing it can help your provider know what medicine is the best treatment.
Your provider may do this test if your child has a fever with no clear cause or your child is very sick.
Usually no preparation is needed for this test, other than helping prepare your child for getting poked with a needle.
Make sure your healthcare provider knows about any medicines (especially antibiotics), herbs, or supplements that your child is taking. Ask your provider before stopping any of your child’s regular medicines.
Having this test will take just a few minutes. A small amount of blood is taken from a vein in your child’s arm with a needle. Blood may be taken from more than 1 site. The blood is collected in tubes and sent to a lab, where it is placed in a container with nutrient substances to see if any germs grow.
Most bacteria grow in a culture within 24 to 48 hours. Fungus may take as long as 30 days to show up. Ask your healthcare provider when and how you will get the result of your test.
A test is negative if it does not find any bacteria of fungus in the blood sample. If your child’s test is negative, your child may be tested again to check the result.
A blood culture test is positive if bacteria or fungus grows in the culture. If the test is positive, different medicines may be tested in the lab to see which medicine will best treat the infection.
Test results are only one part of a larger picture that takes into account your child’s medical history, physical exam, and current health. Sometimes a test needs to be repeated to check the first result. Talk to your healthcare provider about your child’s result and ask questions, such as: