Fecal analysis.
A fecal analysis is a noninvasive laboratory test useful in identifying disorders of the digestive tract. These disorders may include malabsorption, inflammation, infection (bacteria, viruses, or fungi), or cancer. It is performed in combination with blood work, physical examination, x-ray imaging, and endoscopy in order to confirm these conditions. The most common test done on a stool is called fecal occult blood test (FOBT) wherein it can detect traces of blood in the feces.
The role of the nurses during a stool collection and fecal analysis are as follows: proper specimen collection and handling, accurate sample identification, ensure all supplies are appropriate for the collection, and timely transport of the specimen to the laboratory.
INDICATIONS
- Aid in diagnosing disorders related to gastrointestinal (GI) bleeding or medication therapy that results in bleeding
- Assist in the diagnosis of pseudomembranous enterocolitis following the use of broad-spectrum antibiotic therapy
- Help diagnose suspected inflammatory bowel syndrome (IBS)
- Identify the cause of diarrhea of unknown origin
- Investigate disorders of protein digestion
- Screen for colorectal cancer
- Screen for cystic fibrosis
- Determine intestinal parasitic infestation, as indicated by diarrhea of unknown cause
- Evaluate the effectiveness of therapeutic regimen for intestinal malabsorption or pancreatic insufficiency
Steps in collecting a stool specimen
- Collect a fecal sample
Wear clean gloves and collect a stool specimen and put it directly in a leak-proof container with a tight-fitting lid. If the patient is bedridden, collect the specimen in a clean, dry bedpan, and then, using a tongue blade, transfer into a properly labeled container. If doing a rectal swab, insert the swab 2-3 cm through the rectal sphincter, rotate gently, and remove. Transfer swabs in the container. - Fill out the test request form completely
Note on the laboratory request the patient’s demographics, stool consistency, and date and time of collection. Indicate previous or present antibiotic therapy and any pertinent history - Transport the specimen to the laboratory
Send the specimen to the laboratory immediately for processing and analysis. If a liquid or soft stool sample can’t be processed within 30 minutes of passage, placed in a preservative; If a formed stool specimen can’t be studied immediately, place it in a preservative or refrigerator.
METHODS OF EXAMINATION
There are two methods where stool can be examined:
Macroscopic examination: for appearance and color
Microscopic examination: for cell count and presence of meat fibers; leukocyte esterase, for leukocytes; Benedict’s solution (copper sulfate) for reducing substances; guaiac, for occult blood; for trypsin
| Characteristic of stool | Normal findings |
| Appearance | Solid and formed |
| Color | Brown |
| Epithelial cells | Few to moderate |
| Fecal fat | Less than 7 grams of fat per 24 hours |
| Leukocytes (white blood cells) | Negative |
| Meat fibers | Negative |
| Occult blood | Negative |
| Reducing substances | Negative |
| Trypsin | 2+ to 4 + |
ABNORMAL FINDINGS
Abnormal findings in a stool exam may reveal the potential medical diagnosis. These includes:
Unusual appearance:Mucous: Intestinal wall inflammation
Bloody: Excessive intestinal wall irritation or malignancy
Frothy or bulky: Malabsorption
Ribbonlike or slender: Obstruction
Unusual color:Red: Beets and food coloring, lower GI bleed, phenazopyridine hydrochloride compounds, rifampicin
Black: Bismuth (antacid) or charcoal ingestion, iron therapy, upper GI bleeding
Yellow: Rhubarb
Green: Antibiotics, biliverdin, green vegetables
Grayish white: Barium ingestion, bile duct obstruction
Increased:Blood: related to GI bleeding
Occult blood: Diverticular disease, esophagitis, gastritis, esophageal varices, anal fissure, hemorrhoids, infectious diarrhea, inflammatory bowel disease, polyps, tumors, ulcers, Mallory-Weiss tears
Leukocytes: Inflammation of the intestines related to bacterial infections of the intestinal wall, ulcerative colitis, shigellosis, or salmonellosis
Epithelial cells: Inflammatory bowel disorders
Carbohydrates/reducing substances: Inability to digest some sugar, malabsorption syndromes
Fats: Sprue (celiac disease), cystic fibrosis-related to malabsorption, pancreatitis
pH: Related to inflammation in the intestine from colitis, cancer, or antibiotic use
Meat fibers: Pancreatitis, impaired protein digestion
Decreased:Leukocytes: Disorders resulting from toxins, cholera, viral diarrhea, amebic colitis, parasites
Carbohydrates/reducing substances: Cystic fibrosis, sprue, malnutrition, medications such as colchicine or birth control pills
pH: Related to poor absorption of carbohydrate or fat
Trypsin: Malabsorption syndrome, pancreatic deficiency, cystic fibrosis
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