Ova and Parasites, Stool

Ova and Parasites, Stool

Synonym/acronym: O & P.

Common use

To assess for the presence of parasites, larvae, or eggs in stool to assist in diagnosing a parasitic infection.


Stool collected in a clean plastic, tightly capped container.

Normal findings

(Method: Macroscopic and microscopic examination) No presence of parasites, ova, or larvae.


This test evaluates stool for the presence of intestinal parasites and their eggs. Some parasites are nonpathogenic; others, such as protozoa and worms, can cause serious illness.

This procedure is contraindicated for



  • Assist in the diagnosis of parasitic infestation.

Potential diagnosis

Positive findings in:

  • Amebiasis— Entamoeba histolytica infection
  • Ascariasis— Ascaris lumbricoides infection
  • Blastocystis— Blastocystis hominis infection
  • Cryptosporidiosis— Cryptosporidium parvum infection
  • Enterobiasis— Enterobius vermicularis (pinworm) infection
  • Giardiasis— Giardia lamblia infection
  • Hookworm disease— Ancylostoma duodenale, Necator americanus infection
  • Isospora— Isospora belli infection
  • Schistosomiasis— Schistosoma haematobium, S. japonicum, S. mansoni infection
  • Strongyloidiasis— Strongyloides stercoralis infection
  • Tapeworm disease— Diphyllobothrium, Hymenolepiasis, Taenia saginata, T. solium infection
  • Trematode disease— Clonorchis sinensis, Fasciola hepatica, Fasciolopsis buski infection
  • Trichuriasis— Trichuris trichiura infection

Critical findings


Interfering factors

  • Failure to test a fresh specimen may yield a false-negative result.
  • Antimicrobial or antiamebic therapy within 10 days of test may yield a false-negative result.
  • Failure to wait 1 wk after a gastrointestinal study using barium or after laxative use can affect test results.
  • Medications such as antacids, antibiotics, antidiarrheal compounds, bismuth, castor oil, iron, magnesia, or psyllium fiber (Metamucil) may interfere with analysis.

Nursing Implications and Procedure

Potential nursing problems

ProblemSigns & SymptomsInterventions
Infection (tapeworm) (Related to drinking contaminated water; eating food contaminated with fecal matter infested with larva; eating raw or uncooked meat from an infected animal)It is possible that there will be no symptoms; nausea; poor appetite; weakness; abdominal pain; diarrhea; weight loss secondary to inadequate nutrient absorption; fever; the presence of a cystic mass or lumps; allergic reactions to the larvae; bacterial infections; neurologic symptoms; seizuresAdminister prescribed tapeworm medication (praziquantel, albendazole, nitazoxanide); provide education on how to prevent an infection reoccurrence; emphasize vigilant handwashing
Infection (Giardiasis) (Related to contact with infected fecal contaminated food, water, or soil; swallowing infected water while swimming [lakes, rivers, streams]; eating uncooked food containing Giardiasis)Diarrhea; greasy stools; gas; nausea; abdominal pain/cramps; dehydrationAdminister prescribed IV fluids and antibiotics; encourage drinking oral liquids; explain the symptoms of dehydration to be monitored for (especially in children); provide education on how to prevent an infection reoccurrence; teach the patient that family members should stay away from those infected with Giardiasis; emphasize vigilant handwashing
Pain (Related to intestinal infection; inflammation; diarrhea)Self-report of abdominal pain; abdominal bloating; abdominal cramping; emotional symptoms of distress; crying; agitation; facial grimace; moaning; irritability; disturbed sleep; diaphoresis; altered blood pressure and heart rate; nausea; vomitingCollaborate with the patient and physician to identify the best pain management modality to provide relief; ensure compliance with taking ordered antibiotic to clear parasitic infection; refrain from activities that may aggravate pain; use the application of heat or cold to the best effect in managing the pain; monitor pain severity
Nutrition (Related to ingestion of parasitic contaminated food, water)Positive stool culture for parasitic infectionTeach the patient to abstain from eating raw food; teach the patient and family to use vigilant handwashing before meals; emphasize the importance of using clean water for food preparation and drinking


  • 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 diagnosing a parasitic infection.
  • Obtain a history of the patient’s complaints, including a list of known allergens. Document any travel to foreign countries.
  • Obtain a history of the patient’s gastrointestinal and immune systems, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
  • Note any recent therapies that can interfere with test results.
  • 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. Instruct the patient on hand-washing procedures, and inform the patient that the infection may be contagious. Warn the patient not to contaminate the specimen with urine, toilet paper, or toilet water. Address concerns about pain and explain to the patient 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 to avoid medications that interfere with test results.
  • Note that there are no food or fluid restrictions unless by medical direction.


  • Potential complications: N/A
  • 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.
  • Collect a stool specimen directly into the container. If the patient is bedridden, use a clean bedpan and transfer the specimen into the container using a tongue depressor.
  • Specimens to be examined for the presence of pinworms are collected by the “Scotch tape” method in the morning before bathing or defecation. A small paddle with a piece of cellophane tape (sticky side facing out) is pressed against the perianal area. The tape is placed in a collection container and submitted to determine if ova are present. Sometimes adult worms are observed protruding from the rectum.
  • 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.
  • 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.
  • 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

    • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP.
    • Educate the patient with positive findings on the transmission of the parasite, as indicated.
    • Warn the patient that one negative result does not rule out parasitic infestation and that additional specimens may be required.
    • Answer any questions or address any concerns voiced by the patient or family.
  • Expected Patient Outcomes

    • Knowledge
    • States the importance of good hand hygiene to decrease risk of parasitic infection
    • States understanding that anal itching during the nighttime could indicate a enterobiasis (pinworm) infection
    • Skills
    • Demonstrates proficient handwashing
    • Describes changes in food and water handling that will need to be taken to prevent parasitic infection
    • Attitude
    • Complies with the request to clean surfaces to help prevent an ova and parasite infection
    • Complies with the recommendation to take the entire amount of prescribed antibiotics as appropriate to treat infection

Related Monographs

  • Related tests include biopsy intestinal, biopsy liver, biopsy muscle, culture stool, fecal analysis, and IgE.
  • Refer to the Gastrointestinal and Immune systems tables at the end of the book for related tests by body system.
Handbook of Laboratory and Diagnostic Tests, © 2013 Farlex and Partners
References in periodicals archive ?
Related diagnostic tests included ova and parasites, stool cultures, fecal leukocytes, fecal fat, sedimentation rate, chemistry panel, oral cholecystogram, gallbladder ultrasonography, and gastrointestinal radiography, all of which were negative.