Culture - colonic tissue

Definition

A colonic tissue culture is a laboratory test to check for disease-causing bacteria, fungi, or viruses in a sample of tissue from the large intestine.

Alternative Names

Colonic tissue culture

How the test is performed

The doctor removes a piece of tissue from your large intestine during a colonoscopy. For more information on how this procedure is done, see colonoscopy.

The sample is sent to a laboratory where it is placed in a special dish containing a gel on which microoganisms can grow, and stored at a certain temperature. The laboratory team checks the sample daily to see if bacteria, viruses, or fungi have grown.

If certain microorganisms grow, more tests will be done to further identify them. This helps determine the best treatment.

How to prepare for the test

There is no specific preparation needed for a culture. For information on how to prepare for the procedure to remove a piece of tissue from your large intestine, see colonoscopy.

How the test will feel

The laboratory culture does not involve the patient, so there is no pain.

For information on how it will feel to have a piece of large intestine tissue removed, see colonoscopy.

Why the test is performed

Your doctor may order this test if you have signs or symptoms of an infection that can affect the large intestine. A culture is often done when other tests such as a stool culture could not identify the cause of infection.

Normal Values

A normal result means that no disease-causing organisms have grown in the laboratory dish.

Some "healthy" bacteria, called bowel flora, are normally found in the gut. The growth of such bacteria during this test does not mean there is an infection.

Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

What abnormal results mean

An abnormal result means that disease-causing organisms have grown in the laboratory dish. Such organisms may include:

• Clostridium difficile bacteria
• Cytomegalovirus
• Mycobacterium tuberculosis bacteria
• Salmonella bacteria
• Shigella bacteria

These organisms may lead to infectious diarrhea or parasitic or viral infections involving the colon.

What the risks are

A colonic tissue culture poses no risks to the patient. For information on risks related to removing a sample of tissue from the large intestine, see colonoscopy.

Special considerations

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References

Semrad CE, Powell DW. Approach to the patient with diarrhea and malabsorption. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 143.

Steiner TS, Guerrant RL. Principles and syndromes of enteric infection. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 93.