What is a blood culture?

A blood culture is a test that may be ordered by a doctor when it is suspected that someone has an infection caused by either a bacteria or a fungus. The circulatory system is one of the few places in the human body where it is NOT normal to have either bacteria or fungus. Humans live in symbiotic relationships with various types of microbes; many are helpful, or at least not harmful. 

However, the blood...

A blood culture is a test that may be ordered by a doctor when it is suspected that someone has an infection caused by either a bacteria or a fungus. The circulatory system is one of the few places in the human body where it is NOT normal to have either bacteria or fungus. Humans live in symbiotic relationships with various types of microbes; many are helpful, or at least not harmful. 

However, the blood stream is one area where bacteria or fungus are potentially very dangerous. When an infection is suspected, a sample of blood is drawn using a needle inserted into a vein. The sample is placed in a culture dish and observed for growth of any foreign microorganisms. All equipment must be kept sterile, in order to ensure that if any bacteria or fungus is found that the only possible origin is from the blood of the patient. If bacteria or fungus is found in the blood, it is referred to as a sepsis, and is a very serious condition. The microbe may be tested further to determine exactly what type it is, and what treatment is required--for example, a speciic antibiotic. Unless treated with the proper drugs a sepsis can be fatal.