Blood Culture

This test checks for bacteria and yeasts (a type of fungus) growing in your blood. It is often done when you have signs or symptoms of a bacterial infection. These symptoms may include fever, chills, elevated white blood cell count, and fatigue. These may be signs of an infection occurring in other parts of the body. Examples include a urinary tract infection (UTI), pneumonia, diarrhea, or skin infection. If your blood culture is positive, the specific bacteria or yeast causing the infection will be identified. Further antibiotic susceptibility testing will be done. This tells your caregiver which antibiotics will be effective for treatment.


A blood sample is obtained by inserting a needle into a vein in the arm. Multiple samples are collected and different veins are used. This is done for 2 reasons:

  • When multiple samples are done, there is a better chance of finding the infection.

  • Sometimes, despite disinfection of the skin where the blood is collected, you can grow a skin contaminant. This will result in a positive blood culture. This is called a false positive. With multiple samples, there is a better chance of ruling out a false positive.

Tell the person drawing the blood if you are taking any antibiotics.


Adults and Children: No growth

Ranges for normal findings may vary among different laboratories and hospitals. You should always check with your caregiver after having lab work or other tests done to discuss the meaning of your test results and whether your values are considered within normal limits.


Your caregiver will go over the test results with you. Your caregiver will discuss the importance and meaning of your results. He or she will also discuss treatment options and additional tests, if needed.


It is your responsibility to obtain your test results. Ask the lab or department performing the test when and how you will get your results.