Procedure & Contamination of Blood Culture

Submitted on March 27, 2012

What Is Blood Culture?

The test done to detect the presence of microbes in the blood stream is known as a blood culture. When a person is suffering from flu like symptoms, chills or fever, this test is prescribed. If there are any fungi or bacteria that have spread into the blood and are causing these symptoms, they can be detected through this blood test. The results of a culture are used to determine the kind of microbes present in the body. The detection of the microbes is very important in determination of the treatment.


The blood culture procedure is pretty simple. A blood sample is taken by inserting an injection. The collected blood is transferred into special vials or blood culture bottles. These bottles already contain a nutritional broth. For the blood culture collection, about ten ml of blood is collected in each bottle. These bottles allow the clinician to transfer the blood from the syringes into the bottle without the fear of any contamination.

The results of this test are derived after 2-3 days. During this period, the treatment given is usually preliminary, aimed at alleviating the symptoms. Once the test results are out, the treatment is often changed so as to specifically target the infection causing microbes.

Blood Culture Contamination

Though it is not often that the blood taken for a culture test gets contaminated, blood culture contamination is not unheard of. It is one of the most frustrating problems that can be faced by hospitals and doctors. Poor collection techniques or use of an improper bottle for storing the collected blood can contaminate the blood due to exposure to external bacteria and fungi. Such an introduction of post collection microbes can mislead the doctors and cause a misdiagnosis of the problem. Such a misleading diagnosis has both financial and human implications.

The microorganisms that cause diseases and infections usually invade the bloodstream. Though the invasion side is usually local, due to the continuous circulation of blood, microorganisms can quickly spread into the blood stream. While most of these microorganisms can be detected almost immediately after the onset of the initial symptoms, there are some which are not detected even after the initial onset of symptoms. For such microbes, there are other specific tests that can be prescribed. A rapid heart rate, fever and an increase in the count of white blood cells usually warrants a blood culture.

A number of infections and diseases can be identified using a blood culture test.