Fecal Analysis

Fecal Analysis

Synonym/acronym: N/A.

Common use

To assess for the presence of blood in the stool toward diagnosing gastrointestinal bleeding, cancer, inflammation, and infection.

Specimen

Stool.

Normal findings

(Method: Macroscopic examination, for appearance and color; microscopic examination, for cell count and presence of meat fibers; leukocyte esterase, for leukocytes; Clinitest [Bayer Corporation, Pittsburgh, Pennsylvania] for reducing substances; guaiac, for occult blood; x-ray paper, for trypsin.)
CharacteristicNormal Result
AppearanceSolid and formed
ColorBrown
Epithelial cellsFew to moderate
Fecal fatSee “Fecal Fat” monograph
Leukocytes (white blood cells)Negative
Meat fibersNegative
Occult bloodNegative
Reducing substancesNegative
Trypsin2+ to 4+

Description

Feces consist mainly of cellulose and other undigested foodstuffs, bacteria, and water. Other substances normally found in feces include epithelial cells shed from the gastrointestinal (GI) tract, small amounts of fats, bile pigments in the form of urobilinogen, GI and pancreatic secretions, electrolytes, and trypsin. Trypsin is a proteolytic enzyme produced in the pancreas. The average adult excretes 100 to 300 g of fecal material per day, the residue of approximately 10 L of liquid material that enters the GI tract each day. The laboratory analysis of feces includes macroscopic examination (volume, odor, shape, color, consistency, presence of mucus), microscopic examination (leukocytes, epithelial cells, meat fibers), and chemical tests for specific substances (occult blood, trypsin, estimation of carbohydrate). Detection of occult blood is the most common test performed on stool. The prevalence of colorectal adenoma is greater than 30% in people aged 60 and older. Progression from adenoma to carcinoma occurs over a period of 5 to 12 yr; from carcinoma to metastatic disease in 2 to 3 yr.

This procedure is contraindicated for

    N/A

Indications

  • Assist in diagnosing disorders associated with GI bleeding or drug therapy that leads to bleeding
  • Assist in the diagnosis of pseudomembranous enterocolitis after use of broad-spectrum antibiotic therapy
  • Assist in the diagnosis of suspected inflammatory bowel disorder
  • Detect altered protein digestion
  • Detect intestinal parasitic infestation, as indicated by diarrhea of unknown cause
  • Investigate diarrhea of unknown cause
  • Monitor effectiveness of therapy for intestinal malabsorption or pancreatic insufficiency
  • Screen for cystic fibrosis

Potential diagnosis

  • Unusual Appearance
  • Bloody: Excessive intestinal wall irritation or malignancy Bulky or frothy: Malabsorption Mucous: Inflammation of intestinal walls Slender or ribbonlike: Obstruction
  • Unusual Color
  • Black: Bismuth (antacid) or charcoal ingestion, iron therapy, upper GI bleeding Grayish white: Barium ingestion, bile duct obstruction Green: Antibiotics, biliverdin, green vegetables Red: Beets and food coloring, lower GI bleed, phenazopyridine hydrochloride compounds, rifampin Yellow: Rhubarb
  • Increased
  • Blood related to bleeding in the digestive tract Carbohydrates/reducing substances: Malabsorption syndromes, inability to digest some sugars Epithelial cells: Inflammatory bowel disorders Fat pancreatitis, sprue (celiac disease), cystic fibrosis related to malabsorption Leukocytes: inflammation of the intestines related to bacterial infections of the intestinal wall, salmonellosis, shigellosis, or ulcerative colitis Meat fibers: Altered protein digestion, pancreatitis Occult blood: Anal fissure, diverticular disease, esophageal varices, esophagitis, gastritis, hemorrhoids, infectious diarrhea, inflammatory bowel disease, Mallory-Weiss tears, polyps, tumors, ulcers pH: related to inflammation in the intestine from colitis, cancer, or antibiotic use
  • Decreased
  • Carbohydrates sprue, cystic fibrosis, malnutrition, medications such as colchicine (gout) or birth control pills Leukocytes: Amebic colitis, cholera, disorders resulting from toxins, parasites, viral diarrhea pH: related to poor absorption of carbohydrate or fat Trypsin: Cystic fibrosis, malabsorption syndromes, pancreatic deficiency

    Critical findings

      N/A

    Interfering factors

    • Drugs that can cause positive results for occult blood include acetylsalicylic acid, anticoagulants, colchicine, corticosteroids, iron preparations, and phenylbutazone.
    • Ingestion of a diet high in red meat, certain vegetables, and bananas can cause false-positive results for occult blood.
    • Large doses of vitamin C can cause false-negative occult blood.
    • Constipated stools may not indicate any trypsin activity owing to extended exposure to intestinal bacteria.

    Nursing Implications and Procedure

    Potential nursing problems

    ProblemSigns & SymptomsInterventions
    Bleeding (Related to bowel inflammation; irritation; infection; chronic disease)Altered level of consciousness; hypotension; increased heart rate; decreased HGB and HCT; capillary refill greater than 3 sec; cool extremitiesMonitor and trend HGB/HCT, platelet count; increase frequency of vital sign assessment with variances in results; monitor for vital sign trends; administer blood or blood products as ordered; assess diet for iron-rich foods, and foods with vitamin K; discuss the importance of reporting black or tarry stools that are indicative of gastrointestinal bleeding; assess for cultural or religious barriers to blood transfusion
    Pain (Related to infection; inflammation; contractions of diseased bowel)Colicky intermittent abdominal pain; bloating; cramping; distention; self-report of pain; abdominal tenderness; hyperactive bowel sounds; increased pain and cramping with eatingAssess the degree in cramping, colicky abdominal pain, and bloating with eating; auscultate bowel sounds; evaluate tolerance of dairy products in the diet; identify successful pain management strategies that have been used in the past; administer prescribed medications (sulfasalazine, corticosteriods, immunosuppressants, immunomodulators. anticholinergics, antidiarrheal); recommend diversional activities as a pain management modality; collaborate to make necessary dietary alterations that will decrease bowel irritation
    Nutrition (Related to inadequate absorption; decreased caloric intake; nausea; diarrhea with nitrogen loss)Decreased weight; poor wound healing; pedal pedal edema; decreased calcium, potassium, vitamins, zinc, folic acid; skin lesions; muscle wastingMonitor and trend serum calcium, potassium, vitamin K and B12, zinc, and folic acid; take an accurate actual weight daily (not verbally reported or estimated); assess for skin lesions; assess current dietary habits and caloric intake; arrange dietary consult and collaboration to develop an appropriate diet; administer ordered vitamin supplements; discuss the possibility of using total parenteral nutrition if oral intake is not sufficient
    Fluid volume (Related to nausea; vomiting; diarrhea)Hypotension; decreased cardiac output; decreased urinary output; dry skin/mucous membranes; poor skin turgor; sunken eyeballs; increased urine specific gravity; hemoconcentrationAssess current hydration status, skin turgor, check for the presence of dry mucous membranes, assess for decreased urine output, dark urine, hypotension; check stools for occult blood; assess for tarry or black stools (indicative of bleeding); administer IV fluids, blood and blood products as ordered; encourage oral intake

    Pretest

    • Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
    • Patient Teaching: Inform the patient this test can assist in the diagnosis of intestinal disorders.
    • Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex.
    • Obtain a history of the patient’s gastrointestinal system, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
    • Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
    • Review the procedure with the patient. Inform the patient of the procedure for collecting a stool sample, including the importance of good hand-washing techniques. The patient should place the sample in a tightly covered container. Instruct the patient not to contaminate the specimen with urine, water, or toilet tissue. Address concerns about pain and explain that there should be no discomfort during the procedure.
    • Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
    • Instruct the patient not to use laxatives, enemas, or suppositories for 3 days before the test.
    • Instruct the patient to follow a normal diet. If the test is being performed to identify blood, instruct the patient to follow a special diet that includes small amounts of chicken, turkey, and tuna (no red meats), raw and cooked vegetables and fruits, and bran cereal for several days before the test. Foods to avoid with the special diet include beets, turnips, cauliflower, broccoli, bananas, parsnips, and cantaloupe, because these foods can interfere with the occult blood test.

    Intratest

    • Potential complications: N/A
    • Ensure that the patient has complied with medication restrictions; assure laxatives, enemas, or suppositories have been restricted for at least 3 days prior to the procedure.
    • Instruct the patient to cooperate fully and to follow directions.
    • Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date and time of collection, and suspected cause of enteritis; note any current or recent antibiotic therapy.
    • Collect a stool specimen in a half-pint waterproof container with a tight-fitting lid; if the patient is not ambulatory, collect it in a clean, dry bedpan. Use a tongue blade to transfer the specimen to the container, and include any mucoid and bloody portions. Collect specimen from the first, middle, and last portion of the stool. The specimen should be refrigerated if it will not be transported to the laboratory within 4 hr after collection.
    • To collect specimen by rectal swab, insert the swab past the anal sphincter, rotate gently, and withdraw. Place the swab in the appropriate container.
    • Promptly transport the specimen to the laboratory for processing and analysis.

    Post-Test

    • Inform the patient that a report of the results will be made available to the requesting health-care provider (HCP), who will discuss the results with the patient.
    • The American Cancer Society recommends regular screening for colon cancer, beginning at age 50 yr for individuals without identified risk factors. Their recommendations for frequency of screening: annual for occult blood testing (fecal occult blood testing [FOBT] and fecal immunochemical testing [FIT]); every 5 yr for flexible sigmoidoscopy, double contrast barium enema, and CT colonography; and every 10 yr for colonoscopy. There are both advantages and disadvantages to the screening tests that are available today. Methods to use DNA testing of stool are being investigated and await FDA approval. The DNA test is designed to identify abnormal changes in DNA from the cells in the lining of the colon that are normally shed and excreted in stool. The DNA tests under development use multiple markers to identify colon cancers that demonstrate different, abnormal DNA changes. Unlike some of the current screening methods, the DNA tests would be able to detect precancerous polyps. The most current guidelines for colon cancer screening of the general population as well as of individuals with increased risk are available from the American Cancer Society (www.cancer.org), U.S. Preventive Services Task Force (www.uspreventiveservicestaskforce.org), and the American College of Gastroenterology (www.gi.org). Answer any questions or address any concerns voiced by the patient or family.
    • Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.
    • Patient Education

      • Recognize anxiety related to test results.
      • Discuss the implications of abnormal test results on the patient’s lifestyle.
      • Provide teaching and information regarding the clinical implications of the test results, as appropriate.
      • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP.
      • Note that decisions regarding the need for and frequency of occult blood testing, colonoscopy, or other cancer screening procedures should be made after consultation
    • Expected Patient Outcomes

      • Knowledge
      • States the importance of notifying the HCP of black or tarry stools
      • States understanding that untreated disease could result in colon cancer
      • Skills
      • Demonstrates proficiency in the self-administration of ordered vitamin supplements
      • Demonstrates the ability to select a diet that will support bowel health and decrease gastric irritation
      • Attitude
      • Complies with the request to adjust diet to decrease abdominal pain and improve caloric intake
      • Complies with the request to provide a stool specimen for analysis in a timely manner

    Related Monographs

    • Related tests include α1-antitrypsin/phenotyping, barium enema, biopsy intestine, capsule endoscopy, CEA and cancer antigens, chloride sweat, colonoscopy, CT colonoscopy, culture stool, d-xylose tolerance, fecal fat, gliadin antibody, lactose tolerance test, ova and parasites, and proctosigmoidoscopy.
    • Refer to the Gastrointestinal System table at the end of the book for related tests by body system.
    References in periodicals archive ?
    Fecal analysis revealed increases in the microbiota obtained with the probiotics.
    His research interests include food web dynamics and biological interactions, and he has established a laboratory dedicated to fecal analysis in the Laboratory of Genetics, University of Turku.
    This agrees with our fecal analysis results, which suggested that American Robins eat buckthorn at a disproportionate rate relative to the species' fruit abundance.
    Basic techniques, such as venipuncture, intravenous and intraosseous catheter placement, and fecal analysis also are discussed, and radiographic technique and positioning as well as anesthetic induction and monitoring are introduced.
    Most deer diet studies are done by examining rumen samples (stomach contents) or fecal analysis.
    Fecal analysis reflects the metal intake from water, food, tins, aluminum foils and cookware, medicine, etc.
    Monthly fecal analysis for 2003 showed moose relied more heavily on species other than willow in June, most notably Carex spp.
    In the case of gorillas, Michele Goldsmith, an assistant professor with the Tufts Center for Conservation Medicine who has been studying mountain gorillas in Uganda for several years, says such techniques can include fecal analysis to evaluate both diet- and stress-related hormones.
    Studies have shown that fecal analysis is a useful method for determining the food habits of bats (11).
    Benefits for birds include a yearly physical examination, blood tests, fecal analysis, and a nail and wing trim.