What Is A Blood Culture Test?
The blood culture test is a common blood investigation test performed to check the invasion of pathogens in the bloodstream. Foreign pathogens like bacteria, viruses, fungi, or yeast lead to infectious disorders, and a small amount of blood is required as the specimen for the investigation. A blood culture investigation helps to identify the causative organism of the disorder and leads to treatment planning. Some infections cause systemic involvement and affect the body's immune system, thus it is critical to identify the exact germ causing the illness and select the appropriate treatment for the condition.
What Is the Significance of a Blood Culture Test?
Blood culture is one of the oldest and most common blood investigations and helps to determine the causative agent of a disease-causing blood infection. Some of the disorders and complications lead to life-threatening conditions and systemic disorders affecting several internal organs of the body, like sepsis.
Sepsis is an infectious disease that affects the immune system of the body, and it is caused by pathogens present in the bloodstream.
What Is Blood Infection?
Blood infection refers to the invasion of pathogens in the bloodstream, causing sepsis, also known as septicemia. In sepsis, the pathogens tend to release some toxic chemicals that may affect the internal organs of the body and cause life-threatening conditions. The body’s immune system responds to the causative pathogens and releases toxic chemicals which get spread into the internal organs of the body.
Sepsis can lead to dangerous conditions like blood clots, low blood pressure, or multiple organ failure involving the liver, kidneys, and lungs, also called septic shock. Sepsis is common in patients affected with AIDS (acquired immunodeficiency syndrome) or HIV (human immunodeficiency virus), pregnancy, diabetes, hospitalization, or other problems. Sepsis causes high-grade fever, low body temperature, rapid heart rate, fatigue, nausea, and vomiting.
Broad-spectrum antibiotics are indicated for the treatment of blood infections, which attack specific types of bacteria and fight against infections.
What Are the Indications for Blood Culture Tests?
A blood culture test is a common investigation carried out in most cases for the diagnosis of a disease and the specific causative agent. The test helps to determine the best treatment for the disorder.
Following are the condition in which the blood culture test is indicated -
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High-grade fever.
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Fatigue.
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Vomiting.
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Nausea.
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Confusion.
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Urinary tract infection.
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Blood clots.
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Non-healing wounds.
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Low blood pressure.
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Organ failure.
What Is the Procedure for Conducting the Blood Culture Test?
The blood culture test has a simple procedure, and it is done by an experienced healthcare provider such as a nurse, or a phlebotomist who will collect the blood sample by performing the following steps -
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Clean the skin of the arm.
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Insert a thin needle into the vein to withdraw the blood.
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Collecting the blood sample in a test tube for examination.
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Apply pressure over the prick to stop the oozing out of the blood.
The sample of the blood is taken to the lab and mixed with a material called culture to study the type and growth of the causative bacteria. It takes around 24 - 48 hours to get the results of the test. Sometimes this procedure is repeated to get accuracy in the diagnosis of the disorder.
What Are the Interpretations of the Results of the Blood Culture Test?
The blood culture test takes 24 - 48 hours to show the results. The test results can be positive or negative.
In the positive blood culture report, it is interpreted that there is a presence of a specific pathogen which is a major causative factor of the disorder. Meanwhile, the negative test report interprets no pathogen involvement in the respective condition.
It is also advised to conduct the test multiple times to get accuracy because, in many cases, the first test report may show a positive result, and others may show negative results. This happens due to some external factors like sample contamination, use of antibiotics, and appropriate media for the culture of the germs.
What if the Test Results of the Blood Culture Are Negative, but an Individual Still Has the Symptoms?
There is a certain case when the blood culture shows a negative report, but the patient is suffering from the associated signs and symptoms. It could be because the causative agent may be a virus or other pathogens than bacteria. In the lab, some types of bacteria are hard to grow and may show a negative result in the culture test.
What Happens When the Test Results Are Positive?
The blood culture test helps to determine the specific causative pathogen causing the infection. The positive test results indicate the initiation of the treatment for the infections by administration of broad-spectrum antibodies. This leads to targeting a wide group of bacteria and killing the pathogens.
What Are the Risks Involved in Blood Culture Tests?
The blood culture test can lead to complications while performing the procedure. However, it is a commonly used technique.
The following are the risk factors involved in the blood culture test -
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Hematoma - bleeding beneath the skin.
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Excessive bleeding.
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Infections.
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Fainting or dizziness.
Why Is It Advised to Repeat the Blood Culture Test?
- The results of the blood culture test may vary in the same patient, so it is important to take two or three samples of the blood to get accurate test results for treatment planning.
- In some cases, follow-up tests are also advised if the signs and symptoms are still present. It also helps to check the spread of the infection over time in the body.
- The blood culture test may not be able to detect all the types of pathogens involved in the disorder, so other blood tests are indicated.
Conclusion:
Blood culture tests are one of the most common routine tests performed for the diagnosis of a blood infection. It is a simple and cost-effective procedure and helps to determine the causative agent of the infection. It is performed by an experienced healthcare provider and helps in treatment planning.
