To assess for the presence of blood in the stool toward diagnosing gastrointestinal bleeding, cancer, inflammation, and infection.
(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.)
|Appearance||Solid and formed|
|Epithelial cells||Few to moderate|
|Fecal fat||See “Fecal Fat” monograph|
|Leukocytes (white blood cells)||Negative|
|Trypsin||2+ to 4+|
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
- 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
- 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
|Problem||Signs & Symptoms||Interventions|
|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 extremities||Monitor 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 eating||Assess 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 wasting||Monitor 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; hemoconcentration||Assess 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|
- 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.
- 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.
- 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.
- 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
- States the importance of notifying the HCP of black or tarry stools
- States understanding that untreated disease could result in colon cancer
- 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
- 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 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.
Handbook of Laboratory and Diagnostic Tests, © 2013 Farlex and Partners