Definition

Rectal culture is a lab test to identify bacteria and other germs in the rectum that can cause gastrointestinal symptoms and disease.

Alternative Names

Culture - rectal

How the Test is Performed

A cotton swab is placed into the rectum. The swab is rotated gently, and removed.

A smear of the swab is placed in culture media to encourage the growth of bacteria and other organisms. The culture is watched for growth.

The organisms can be identified when growth is seen. More tests may be done to determine the best treatment.

How to Prepare for the Test

The health care provider does a rectal exam and collects the specimen.

How the Test will Feel

There may be pressure as the swab is inserted into the rectum. The test is not painful in most cases.

Why the Test is Performed

The test is done if your provider suspects that you have an infection of the rectum, such as gonorrhea or chlamydia. It may also be done instead of a fecal culture if it is not possible to get a specimen of feces.

The rectal culture may also be performed in a hospital or nursing home setting. This test shows if someone carries vancomycin-resistant enterococcus (VRE) in their intestine. This germ can be spread to other patients.

Normal Results

Finding bacteria and other germs that are commonly found in the body is normal.

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

What Abnormal Results Mean

Abnormal results may mean you have an infection. This may be:

• Bacterial infection
• Parasitic enterocolitis
• Gonorrhea

Sometimes a culture shows that you are a carrier, but you may not have an infection.

A related condition is proctitis.

Risks

There are no risks.

References

Batteiger BE, Tan M. Chlamydia trachomatis (trachoma and urogenital infections). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 180.

Marrazzo JM, Apicella MA. Neisseria gonorrhoeae (Gonorrhea). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 212.

Melia JMP, Sears CL. Infectious enteritis and proctocolitis. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 110.

Plourde AR, Beavis KG. Specimen collection and handling for diagnosis of infectious diseases. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 66.

Siddiqi HA, Rabinowitz S, Axiotis CA. Laboratory diagnosis of gastrointestinal and pancreatic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 23.