A stool test is a series of tests performed on a stool sample (stool) to help diagnose certain conditions that affect the digestive tract. These conditions may include infection (such as parasites, viruses or bacteria), poor nutrient absorption or cancer.
![Fecal Examination](https://www.labtestsguide.com/wp-content/uploads/2020/02/Fecal-Examination-1024x576.jpg)
Also Known as: Stool Analysis, Stool Examination, Stool Test, Fecal Test, Fecal Analysis, Fecal Examination
Related Tests: Stool Occult Blood, Stool Reducing substances, Fecal Examination, Fecal Occult Blood, Fecal Analysis, Stool Test
Why get Tested:
- To evaluate the function and integrity of the GI tract.
- To rule out the presence of WBCs and RBCs.
- To find ova or parasites.
- To see the presence of fat for malabsorption syndrome.
- For screening of colon cancer.
- For asymptomatic ulceration of GI tract.
- Evaluate diseases in the presence of diarrhea and constipation.
- Summary of stool studies are done to evaluate:
- Intestinal bleeding.
- Infestation.
- Inflammatory diseases.
- Malabsorption.
- Different causes of diarrhea.
When to Get Tested:
A doctor may order a stool collection to test for a variety of possible conditions, including:
- allergy or inflammation in the body, such as part of the evaluation of milk protein allergy in infants
- infection, as caused by some types of bacteria, viruses, or parasites that invade the gastrointestinal system
- digestive problems, such as the malabsorption of certain sugars, fats, or nutrients
- bleeding inside of the gastrointestinal tract
Sample Required :
- Fresh stool can be examined immediately to detect moving organisms.
- Stool in 10% formalin can be used for helminths and protozoa.
- The feces in formalin-ethyl acetate are used to concentrate the feces.
- The smallest amount of stool needed for the test is 2 to 5 grams.
Precautions for Sample :
- Advise patients the following for at least 48 hours before stool collection:
- Avoid mineral oils.
- Do not take bismuth.
- Antibiotics such as tetracyclines.
- Antidiarrheal medications that are not absorbent.
- Avoid antimalarial drugs.
- The patient should not have a barium ingestion test before the stool test.
- For Occult blood, stop drugs that contain iron, meat and fish at least 48 hours before collection.
- Warm stools are better for ovules and parasites.
- Do not refrigerate feces for eggs and parasites.
- Feces for ovules and parasites can be collected in formalin and polyvinyl alcohol. These are used as fixative.
- If there is blood or mucus, that should be included in the stool. Because most pathogens are found in this substance.
- Examine feces before giving antibiotics or other drugs.
- Semiformed feces should be examined within 60 minutes after collection.
- Liquid feces should be examined within the first 30 minutes.
- Solid stool should be examined within the first hour of collection.
- Trophozoites degenerate into liquid stools quickly, so you should examine the stool in 30 minutes.
- In the case of cases of constipation, use a non-residual purgative the night before stool collection.
Preservatives of Stool :
- The preservatives for the wet preparation are:
- 10% saline formalin for wet preparation. This is the best preservative since it kills bacteria and preserves protozoa and helminths.
- Sodium formalin acetate.
- Iodine formalin formalin. This is a good preservative for stool collection.
- For staining use polyvinyl alcohol.
- Avoid preservatives for stool culture.
- Usually three parts of the preservatives and one part of the stool.
Examinations:
- Physical Examination
- Quantity 2.Gross Appearance
- Color
- Consistency
- Chemical Examination
- pH
- Specific Gravity
- Water Contents
- Occult Blood
- Reducing substances
- Porphyrins
- Urobilinogen
- Sodium
- Potassium
- Chloride
- Nitrogen
- Tryspin
- Lipids
- Osmolality
- Microscopic Examination
- WBCs
- RBCs
- Parasites
- Yeast
- Bacteria
- Viruses
- OVA and Cyst
- Undigested foods
- Meat fibers, starch
Normal Stool Findings :
Note: This is a Normal Stool Findings, For Abnormal Stool Findings please study one by one characters.
Physical Examination :
Characters | Normal values |
---|---|
Gross Appearance | May see vegetables, seeds, and fibers |
Color | Brown |
Odor | Variable depends upon the bacterial fermentation |
Consistency | Variable soft to semiformed |
Amount | 100 to 200 g/day |
Mucous | Normally absent |
Blood grossly | Negative |
Parasites | Negative |
Chemical Examinations:
Characters | Normal values |
---|---|
pH | Neutral and maybe 7.0 to 7.5 |
Water contents | 75% |
Occult blood | Negative |
Reducing substances | Negative <0.25 g/dL |
Porphyrins | Corporphyrins = 400 to 1200 µg/day |
Uroporphyrins = 10 to 14 µg/day | |
Urobilinogen | 50 to 300 mg/day |
Sodium | 5.8 to 9.8 meq/day |
Potassium | 15.7 to 20.7 meq/day |
Chloride | 2.5 to 3.9 meq/day |
Nitrogen | <2.5 g/day |
Trypsin | 20 to 95 U/g |
Lipids | 0 to 6 g/day |
Osmolality | 200 to 250 mOsm |
Microscopic Examinations:
Characters | Normal values |
---|---|
WBCs | Negative |
RBCs | Negative |
Parasites | Negative |
Yeast | Negative |
Bacteria | Negative |
Viruses | Negative |
Ova and cyst | Negative |
Undigested foods | Negative to a small amount |
Meat fibers, starch | Negative to a small amount |
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Possible References Used