How the Test is Performed

A stool sample is needed.

There are many ways to collect the sample. One way is to catch the stool on plastic wrap that is loosely placed over the toilet bowl and held in place by the toilet seat. Then, put the sample in a clean container. One test kit supplies a special toilet tissue that you use to collect the sample. You then put the sample in a clean container.

For infants and young children in diapers, line the diaper with plastic wrap. Try to place the plastic wrap in a way that separates the stool from urine so you can get a better sample.

In the laboratory, a technician places a sample of the specimen in a special dish filled with a gel that encourages any microorganisms present to grow. The culture is watched for growth. If there is growth, the organisms are identified. The lab technician may also do more tests to determine the best treatment.

How to Prepare for the Test

You will get a collection container for the stool specimen. Return the sample to the laboratory as soon as possible. Do not include toilet paper or urine in the specimen.

How the Test Will Feel

There is no discomfort.

Why the Test is Performed

The test is performed when you have gastrointestinal distress and your doctor suspects that an infection is the cause. It may be performed if you have severe, persistent (won't go away), or recurrent (keeps coming back) diarrhea without a known cause.

It may also be done if you have diarrhea and have recently taken antibiotics, to see if bacteria such as C. difficile (which can cause diarrhea after people take antibiotics) are now in the intestine.

Normal Results

Normal fecal organisms are present.

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

Abnormal results may indicate an intestinal infection.

Risks

There are no risks.

Considerations

Often other stool tests are done in addition to the culture, such as:

• Gram stain of stool
• Fecal smear
• Stool ova and parasites exam

Alternative Names

Stool culture; Culture - stool

References

DuPont HL. Approach to the patient with suspected enteric infection. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 305.

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.

Update Date: 5/4/2012

Reviewed by: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.