Fecal smear is a laboratory test to check a stool sample for bacteria and other germs that can cause diseases in the digestive tract.
How the test is performed
A stool sample is needed.
There are many ways to collect the sample. You can catch the stool on plastic wrap that is loosely placed over the toilet bowl and held in place by the toilet seat. One test kit supplies a special toilet tissue that you use to collect the sample. When finished, put the sample in a clean container from your health care provider's office.
To collect the sample from a child in diapers, line the diaper with plastic wrap. If the plastic wrap is positioned properly, you can separate the stool from the child's urine. Preventing the mixing of urine and stool will give a better sample. When finished, put the sample in a clean container given to you by your health care provider's office.
Make sure you follow your health care provider's instructions for returning the sample. Return the sample to the laboratory as soon as possible. The sample should not include toilet tissue or urine.
The stool sample is sent to a lab where a small amount is placed on a slide. The slide is placed under a microscope and checked for the presence of bacteria, fungi, or viruses. A stain may be placed on the sample that highlights certain germs under the microscope.
How to prepare for the test
There is no preparation needed.
How the test will feel
There is no discomfort.
Why the test is performed
Your health care provider may order this test if you have severe diarrhea that will not go away or that keeps returning. The test result may be used to select the correct antibiotic treatment.
A normal result means there are no disease-causing germs present.
Normal value ranges may vary slightly among different laboratories. Talk to your health care provider about the meaning of your specific test results.
What abnormal results mean
An abnormal result means that abnormal bacteria or other organisms have been found in the stool sample, which may be due to an infection of the digestive tract.
What the risks are
There are no risks associated with a fecal smear.
DuPont HL. Approach to the patient with suspected enteric infeciton. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011: chap 291.
Semrad CE. Approach to the patient with diarrhea and malabsorption. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011: chap 142.
Giannella RA. Infectious enteritis and proctocolitis and bacterial food poisoning. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger & Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 107.
Croft AC, Woods GL. Specimen collection and handling for diagnosis of infectious diseases. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 63.
Salwen MJ, Siddiqi HA, Gress FG, Bowne WB. Laboratory diagnosis of gastrointestinal and pancreatic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 22.
Fritsche TR, Selvarangan R. Medical parasitology. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 62.
Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington; and 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. Health Solutions, Ebix, Inc.