Ova and Parasites Examination

Additional Information:

UFHPL Epic order code: LAB2010

CPT Code(s):

87177, 87209

Collection Procedure:

  • Sputum: If paragonimiasis or echinococcosis is suspected, submit specimen in 10 percent formalin.
  • Feces: Submit specimens in a parasite preservative kit. Inoculate both the PVA and the formalin tubes. Fresh feces should not be submitted. State the preliminary diagnosis.
  • Other: Contact the laboratory at 888.375.LABS (5227) for specific instructions.
  • All: Multiple specimens may be necessary to recover ova or trophozoites. Three specimens are recommended (each is charged).
Fecal specimens for parasitic examination should be collected before initiation of antidiarrheal therapy or antiparasitic therapy. The highest yield on hospitalized patients occurs when diarrhea is present on admission or within 72 hours of admission. The onset of diarrhea more than 72 hours after admission is usually caused by Clostridium difficile toxin rather than parasites or the usual stool pathogens. The following recommendations are made for efficient and cost-effective diagnosis of diarrheal disease in patients admitted with gastroenteritis.

  • Submit one or two specimens per diarrheal illness immediately.
  • If those are negative, submit an additional specimen after five days.
  • Patients who are immunocompromised by AIDS, malignancy, or immunosuppressive therapy may require additional testing for unusual stool pathogens.

Specimen Requirements:

Special Instructions: Include any pertinent clinical and travel history on the test requisition form.

Patient Preparation: Usual aseptic technique

Type: Sputum or feces

Container/Tube: O & P transport container with formalin and PVA (Para-Pak® pink and gray)

Sample Volume: 3 to 4 mL sputum or 5 mL feces

Minimum Volume: 3 mL

Storage: Store specimens at room temperature.

Rejection Criteria:
  • Because parasite morphology will not be preserved, specimens sent on diaper or tissue paper are not acceptable to the laboratory because of risk to lab personnel.
  • Grossly leaking specimens may not be processed.
  • Specimen containing interfering substances (eg, castor oil, bismuth, Metamucil┬«, barium specimens delayed in transit and those contaminated with urine) will not have optimal yield.
  • Unlabeled specimen or name discrepancy between specimen and test request label; expired transport device
  • Specimen not received in O & P preservative transport containers with formalin and PVA


This test is used to establish a diagnosis of parasitic infestation. It includes the concentration of material and examination of specimen for ova and parasites by conventional iodine/saline and trichrome staining. This test will not detect Cryptosporidium, Cyclospora cayetanensis or Microsporidium.


One negative result does not rule out the possibility of parasitic infestation. Stool examination for Giardia may be negative in early stages of infection, in patients who shed organisms cyclically, and in chronic infections.1 The sensitivity of microscopic methods for the detection of Giardia range from 46% to 95%.2 Tests for Giardia antigen may have a higher yield.3


Administration of barium, bismuth, Metamucil®, castor oil, mineral oil, tetracycline therapy, administration of antiamebic drugs within one week prior to test. Purgation contraindicated for pregnancy, ulcerative colitis, cardiovascular disease, child younger than five years of age, appendicitis or possible appendicitis.


Formalin concentrate and trichome stain

Reference Values:

No parasites seen