Stool Test (Stool Analysis): Types, Normal Results and How to Read Your Report

A stool test (also called a stool analysis or fecal test) looks at a small sample of your poop to find the cause of diarrhea, belly pain, bleeding or poor digestion, or to screen for colorectal cancer^[3][7]. This guide walks through a full report, then shows how the parts fit together. Each test has its own page in our stool markers guide.

What does a stool test show? A full report, annotated

Labs group stool results into blocks: what the sample looks like, what the microscope sees, chemistry, inflammation and digestion markers, and infection tests^[7]. Here is what a broad report can look like after a week of diarrhea.

Fictitious example of a stool test report (United States format)

Test	Result	Reference range	Flag
Color	Brown	Brown
Consistency	Watery	Formed	A
Occult blood (FIT)	Negative	Negative
Fecal leukocytes (WBC)	Present	None seen	A
Ova and parasites	No ova or parasites seen	None seen
GI pathogen panel (PCR): Campylobacter	Detected	Not detected	A
GI pathogen panel (PCR): other targets	Not detected	Not detected
Fecal calprotectin	186 µg/g	< 50 µg/g	H
Pancreatic elastase (fecal)	412 µg/g	> 200 µg/g

1. Appearance first. Color and consistency have no number. "Watery" simply describes the diarrhea you already have.
2. Negative, Not detected, None seen all mean the lab did not find that item in this sample, not that it can never be there.
3. A (abnormal) is used for yes/no results; H (high) for numbers above the range. The flag never replaces the reading of the whole report.
4. The story here: a bacterium was found, white blood cells are present and calprotectin is raised. Together they fit a bacterial gut infection, which can raise calprotectin on its own^[4].
5. Units: calprotectin and elastase are in micrograms per gram of stool (µg/g); always compare with the range printed by your lab.

What are the different types of stool tests?

No lab runs every test on every sample. Your clinician picks them from your symptoms, travel, medicines and age. The table gives the usual "normal" answer; your lab's range always wins.

Main stool tests, what they look for and their usual normal result

Test	What it looks for	Usual normal result	Full guide
Color, consistency, mucus, visible blood	How the stool looks	Brown and formed; no blood, a little mucus can be normal[7]	Stool color chart, Bristol stool types
Fecal occult blood (FIT or guaiac)	Blood you cannot see	Negative[3]	Fecal occult blood test
Fecal leukocytes, red blood cells	Signs of an inflamed or bleeding bowel under the microscope	None seen[7]	White blood cells in stool
Ova and parasites (O&P)	Parasites and their eggs	None seen[2]	Ova and parasites exam
Stool culture	Bacteria such as Salmonella, Shigella or Campylobacter	No abnormal organisms[1]	Stool culture test
GI pathogen panel (multiplex PCR)	The genes of many bacteria, viruses and parasites at once	Not detected	Stool PCR panels
C. difficile toxin or gene	Diarrhea after antibiotics or a hospital stay	Negative or not detected	C. difficile toxin test
Fecal calprotectin	Inflammation of the bowel lining	Under 50 µg/g from age 4 to 49[7]; higher in young children	Fecal calprotectin
Pancreatic elastase	Whether the pancreas makes enough digestive enzymes	Over 200 µg/g[5]	Fecal elastase
Fecal fat	Fat that was not absorbed	72-hour collection: under 6 g a day[7]	Fat droplets in stool
H. pylori stool antigen	The stomach bacterium behind many ulcers	Negative[6]	H. pylori stool antigen
pH, reducing substances	Sugars that were not absorbed, mostly in children	pH 7.0 to 7.5; below 5.5 is acidic[7]	Stool pH

Two groups are worth keeping apart. Screening tests (FIT, guaiac test, FIT-DNA) look for colorectal cancer in people without symptoms^[11]. Diagnostic tests (culture, PCR, O&P, calprotectin, elastase) look for the cause of symptoms you already have.

How do you read stool test results together?

A single line rarely gives the answer. These are the patterns doctors look for most often.

Germ found, signs of inflammation

A positive culture or PCR with white blood cells points to a bacterial infection: white cells are typical of bacterial diarrhea, not of viral or parasitic diarrhea^[7]. Calprotectin can rise with some bacterial infections too^[4], so a high value during an infection does not mean Crohn's disease. Your provider may simply recheck it a few weeks later^[4].

PCR positive, culture asked as well

PCR panels are fast and are replacing culture in many labs^[1]. When a panel finds a bacterium, US guidelines ask for a culture of the same sample, for public health tracking and when antibiotic choice depends on susceptibility results^[8]. A culture ordered after a positive PCR is routine, not a sign that something is wrong.

No germ found, calprotectin high and staying high

Inflammation without infection, confirmed on a repeat test, is the pattern that leads to a gastroenterology referral, often with a colonoscopy, to look for ulcerative colitis or Crohn's disease. Calprotectin can also be somewhat high with NSAIDs, celiac disease or colorectal cancer^[4].

Everything normal, symptoms still there

Normal calprotectin makes bowel inflammation unlikely^[4]. For long-lasting watery diarrhea, US gastroenterologists recommend calprotectin or lactoferrin, a Giardia antigen or PCR test rather than a routine O&P (unless you traveled), and celiac blood tests before settling on irritable bowel syndrome^[9].

Low elastase with fat in the stool

Greasy, foul-smelling stools, an elastase under 200 µg/g and excess fat point toward the pancreas. Between 100 and 200 µg/g suggests moderate and under 100 µg/g severe exocrine pancreatic insufficiency; watery stool can falsely lower the result^[5]. Chronic pancreatitis is one cause.

Hidden blood found

A positive FIT means bleeding somewhere in the digestive tract, not necessarily cancer^[3]. After a positive screening stool test, a colonoscopy is needed to complete the screening^[11]. Blood you can see is a different situation: read our page on visible blood in stool.

Negative O&P, still suspicious

A negative O&P can mean there were too few parasites in that sample^[2]; labs often ask for three samples, and Giardia is found in a single sample in only 50 to 70% of cases^[7]. If you saw something moving, our guide to worms in stool explains which test fits.

What should you not do before a stool test?

Most stool tests need no special preparation and no fasting^[2][3]. A few do. Check each item with the person who ordered the test, and never stop a medicine without asking.

• Guaiac blood test: you may be told to avoid NSAIDs, vitamin C above 250 mg a day, red meat and some raw fruits and vegetables beforehand. FIT usually needs no diet change^[3].
• H. pylori antigen: some medicines must be stopped for two weeks to a month^[6], usually antibiotics for 4 weeks and acid-reducing proton pump inhibitors for 1 to 2 weeks^[7].
• Calprotectin: mention NSAIDs (aspirin, ibuprofen, naproxen) and proton pump inhibitors, which can affect the result^[4].
• Elastase: a solid or semi-solid sample is best; pancreatic enzyme pills may need to be paused^[5].
• Collection: catch the stool on plastic wrap or in the container, without urine, toilet water or toilet paper, and return it to the lab as soon as possible^[1].
• Tell the lab about recent travel, antibiotics and a hospital stay: they change which tests make sense^[8].

When should you see a doctor?

For black stool without these signs, see black stool causes and tests.

Frequently asked questions

Can a stool test detect colon cancer?

Screening stool tests look for hidden blood (FIT, done once a year) or blood plus altered DNA (FIT-DNA). They do not diagnose cancer: a positive result leads to a colonoscopy^[11]. See our guide to colorectal cancer.

Is a stool test as good as a colonoscopy?

Both are recommended screening options for adults at average risk^[10]. A colonoscopy looks at the whole colon and can remove polyps during the exam; a stool test is done at home but must be repeated regularly^[11].

Do I need a new stool test after treatment?

For most bowel infections, no: repeat testing is not recommended once diarrhea has resolved, except when local health rules require it for child care or some jobs^[8]. H. pylori is an exception: a test after treatment checks that the bacterium is gone^[6].

Why was only one C. difficile sample requested?

For C. difficile, one diarrheal sample is enough; extra samples do not find more cases^[8].

Related tests and guides

• Stool culture testHow bacteria are grown and identified, and what susceptibility results add.
• Fecal calprotectinThe inflammation marker that separates IBD from IBS.
• Fecal occult blood testWhat a positive FIT or guaiac result means next.
• Ova and parasites examWhy the lab often asks for several samples.
• Green stool causes and testsWhen a change of color deserves a stool test.

References

1. MedlinePlus Medical Encyclopedia. Fecal culture. medlineplus.gov (accessed October 29, 2026)
2. MedlinePlus. Ova and parasite test. medlineplus.gov (accessed October 29, 2026)
3. MedlinePlus. Fecal occult blood test (FOBT). medlineplus.gov (accessed October 29, 2026)
4. MedlinePlus. Calprotectin stool test. medlineplus.gov (accessed October 29, 2026)
5. MedlinePlus. Stool elastase. medlineplus.gov (accessed October 29, 2026)
6. MedlinePlus. Helicobacter pylori (H. pylori) tests. medlineplus.gov (accessed October 29, 2026)
7. Kasırga E. The importance of stool tests in diagnosis and follow-up of gastrointestinal disorders in children. Turk Pediatri Ars. 2019;54(3):141-148. PMID: 31619925 (accessed October 29, 2026)
8. Shane AL, Mody RK, Crump JA, et al. 2017 Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea. Clin Infect Dis. 2017;65(12):e45-e80. doi:10.1093/cid/cix669 (accessed October 29, 2026)
9. Smalley W, Falck-Ytter C, Carrasco-Labra A, Wani S, Lytvyn L, Falck-Ytter Y. AGA clinical practice guidelines on the laboratory evaluation of functional diarrhea and diarrhea-predominant irritable bowel syndrome in adults (IBS-D). Gastroenterology. 2019;157(3):851-854. doi:10.1053/j.gastro.2019.07.004 (accessed October 29, 2026)
10. US Preventive Services Task Force. Screening for colorectal cancer: US Preventive Services Task Force recommendation statement. JAMA. 2021;325(19):1965-1977. doi:10.1001/jama.2021.6238 (accessed October 29, 2026)
11. Centers for Disease Control and Prevention. Screening for colorectal cancer. cdc.gov (accessed October 29, 2026)
12. US Departments of Labor, Health and Human Services, and the Treasury. FAQs about Affordable Care Act implementation, Part 51 (Q7). dol.gov (accessed October 29, 2026)

This article is general health information. It does not replace a medical examination, diagnosis or treatment. With black or bloody stool, high fever, severe pain or dehydration, seek care without waiting.