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Home > Health Library > Stool Analysis
A stool analysis is a series of tests done on a stool (feces) sample to help diagnose certain conditions affecting the digestive tract. These conditions can include infection (such as from parasites, viruses, or bacteria), poor nutrient absorption, or cancer.
For a stool analysis, a stool sample is collected in a clean container and then sent to the laboratory. Laboratory analysis includes microscopic examination, chemical tests, and microbiologic tests. The stool will be checked for color, consistency, amount, shape, odor, and the presence of mucus. The stool may be examined for hidden (occult) blood, fat, meat fibers, bile, white blood cells, and sugars called reducing substances. The pH of the stool also may be measured. A stool culture is done to find out if bacteria may be causing an infection.
Stool analysis is done to:
Many medicines can change the results of this test. You will need to avoid certain medicines depending on which kind of stool analysis you have. You may need to stop taking medicines such as antacids, antidiarrheal medicines, antiparasite medicines, antibiotics, laxatives, or nonsteroidal anti-inflammatory drugs (NSAIDs) for 1 to 2 weeks before you have the test. Be sure to tell your doctor about all the nonprescription and prescription medicines you take.
Be sure to tell your doctor if you have:
If your stool is being tested for blood, you may need to avoid certain foods for 2 to 3 days before the test. This depends on what kind of stool test you use. And do not do the test during your menstrual period or if you have active bleeding from hemorrhoids. If you aren't sure about how to prepare, ask your doctor.
Do not use a stool sample for testing that has been in contact with toilet bowl cleaning products that turn the water blue.
Stool samples can be collected at home, in your doctor's office, at a medical clinic, or at the hospital. If you collect the samples at home, you will be given stool collection kits to use each day. Each kit contains applicator sticks and two sterile containers.
You may need to collect more than one sample over 1 to 3 days. Follow the same procedure for each day.
Collect the samples as follows:
Take the sealed container to your doctor's office or the lab as soon as you can. You may need to deliver your sample to the lab within a certain time. Tell your doctor if you think you may have trouble getting the sample to the lab on time.
If the stool is collected in your doctor's office or the hospital, you will pass the stool in a plastic container that is inserted under the toilet seat or in a bedpan. A health professional will package the sample for lab analysis.
You will need to collect stool for 3 days in a row if the sample is being tested for quantitative fats. You will start to collect stool on the morning of the first day. The samples are placed in a large container and then refrigerated.
You may need to collect several stool samples over 7 to 10 days if you have digestive symptoms after traveling outside the country.
Sometimes a stool sample is collected using a rectal swab that contains a preservative. The swab is inserted into the rectum, rotated gently, and then withdrawn. It is placed in a clean, dry container and sent to the lab right away.
The test will take a few minutes each time you take a sample.
There is no pain while collecting a stool sample. If you are constipated, straining to pass stool may be painful.
If your health professional uses a rectal swab to collect the sample, you may feel some pressure or discomfort as the swab is inserted into your rectum.
Any stool sample may contain germs that can spread disease. Make sure to carefully wash your hands and use careful handling techniques to avoid spreading infection.
Each lab has a different range for what's normal. Your lab report should show the range that your lab uses for each test. The normal range is just a guide. Your doctor will also look at your results based on your age, health, and other factors. A value that isn't in the normal range may still be normal for you.
A stool analysis may check values for pH, reducing factors, and fat.
Stool analysis test results usually take at least 1 to 3 days.
The stool appears brown, soft, and well-formed in consistency.
The stool does not contain blood, mucus, pus, undigested meat fibers, harmful bacteria, viruses, fungi, or parasites.
The stool is shaped like a tube.
The stool is black, red, white, yellow, or green.
The stool is liquid or very hard.
There is too much stool.
The stool contains blood, mucus, pus, undigested meat fibers, harmful bacteria, viruses, fungi, or parasites.
The stool contains low levels of enzymes, such as trypsin or elastase.
Many conditions can change the results of a stool analysis. Your doctor will talk with you about any abnormal results that may be related to your symptoms and past health.
Current as of:
June 17, 2021
Author: Healthwise StaffMedical Review: Adam Husney MD - Family MedicineMartin J. Gabica MD - Family Medicine
Current as of: June 17, 2021
Author: Healthwise Staff
Medical Review:Adam Husney MD - Family Medicine & Martin J. Gabica MD - Family Medicine
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