Test ID: OPE Ova and Parasite, Travel History or Immunocompromised, Feces
Ordering Guidance
This test should be ordered when suspicion of parasitic infection is based on travel history in endemic areas or when a patient is immunocompromised.
For non-fecal specimens, including duodenal aspirate and colonic washing, for ova and parasitic examination, order OAPNS / Ova and Parasite, Microscopy, Varies.
If possible adult worms or proglottids are identified in stool or the patient's undergarments, they should be placed in 70% alcohol and submitted for PARID / Parasite Identification, Varies.
If specific organisms or disease states are suspected, see below:
If Acanthamoeba is suspected, order ACARP / Acanthamoeba species Molecular Detection, PCR, Ocular.
If Cryptosporidium is suspected, order CRYPS / Cryptosporidium Antigen, Feces.
If Cyclospora is suspected, order CYCL / Cyclospora Stain, Feces.
If free-living amebae are suspected, order FLARP / Free-Living Amebae Molecular Detection, PCR, Varies.
If Giardia is suspected, order GIAR / Giardia Antigen, Feces.
If microsporidia are suspected, order LCMSP / Microsporidia species, Molecular Detection, PCR, Varies.
If pinworm is suspected, order PINW / Pinworm Exam, Perianal.
If scabies is suspected, order PARID / Parasite Identification, Varies.
If Schistosoma is suspected, order SHUR / Schistosoma Exam, Urine.
If Trichomonas vaginalis is suspected, order TVRNA / Trichomonas vaginalis, Nucleic Acid Amplification, Varies.
If worms or worm segments are submitted, order PARID / Parasite Identification, Varies.
If respiratory specimens or tissue are submitted, order OAPNS / Ova and Parasite, Microscopy, Varies.
Additional Testing Requirements
Parasites are shed irregularly in stool and examination of a single specimen does not guarantee detection. Therefore, it is strongly recommended that multiple stool specimens be submitted for ova and parasite analysis. At least 3 specimens should be collected. If multiple ova and parasite collections are requested, instruct patient to collect a specimen at least 12 hours after last collection.
Specimen Required
Patient Preparation: Specimen collection should be delayed for 7 to 10 days after administration of barium, bismuth, kaolin, magnesia, castor oil or mineral oil, and 2 to 3 weeks after antibiotics have been given since these may interfere with identification of protozoa.
Specimen Type: Feces
Supplies: ECOFIX Stool Transport Vial (Kit) (T790)
Preferred: ECOFIX preservative
Acceptable: 10% Buffered Formalin Stool Transport plus Zinc Polyvinyl Alcohol (Zn PVA) Stool Transport (one of each)
Specimen Volume: Portion of stool: 2 g or 2 mL
Collection Instructions:
1. Follow instructions on the container as follows:
a. Place specimen into Ecofix preservative vial or one 10% formalin AND one Zn PVA preservative vial within 30 minutes of passage or collection. Refer to the fill line on the preservative vial. Do not fill above the line indicated on the container.
b. Mix the contents of the tube with the spoon, twist the cap to close tightly, and shake vigorously until the contents are well mixed.
Additional Information:
1. Stool placed in 10% buffered formalin can be accepted if accompanied by Zn PVA-preserved specimen; 10% buffered formalin-preserved specimens submitted without an accompanying Zn PVA-preserved specimen will be canceled.
2. Specimen submitted in low viscosity (LV)-PVA, mercury PVA or copper (Cu)-PVA will be rejected.
Forms
If not ordering electronically, complete, print, and send 1 of the following with the specimen:
-Microbiology Test Request (T244)
-Gastroenterology and Hepatology Test Request (T728)
-General Test Request (T239)
Useful For
Detecting and identifying parasitic protozoa and eggs and larvae of parasitic helminths in stool specimens
Testing Algorithm
The following algorithms are available:
Special Instructions
Method Name
Microscopic
Reporting Name
Ova and Parasite, Microscopy, FSpecimen Type
FecalSpecimen Minimum Volume
5 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Fecal | Ambient (preferred) | 21 days | |
Refrigerated | 21 days |
Clinical Information
A variety of different parasites may be found in fecal specimens, duodenal aspirates, and other intestinal specimens. These parasites may include protozoa (microscopic unicellular eukaryotes) and helminths (aka worms). Infection is often asymptomatic, but symptoms range from diarrhea and malnutrition, intestinal obstruction, and rarely, death.
The most common intestinal reported parasites in fecal specimens are Giardia intestinalis (aka Giardia duodenalis, Giardia lamblia) and Cryptosporidium species. Both parasites may cause watery diarrhea and are endemic in the United States. The best tests for these 2 common parasites are parasite-specific fecal antigen tests (GIAR / Giardia Antigen, Feces and CRYPS / Cryptosporidium Antigen, Feces).
Other parasites are less commonly seen in the United States, and this test is the appropriate test for their detection. See Parasitic Investigation of Stool Specimens Algorithm for determining which test should be ordered based on the patient's exposure history and risk factors. If evaluating a patient for diarrhea, see Laboratory Testing for Infectious Causes of Diarrhea Algorithm.
Reference Values
Negative
If positive, organism identified
Interpretation
A positive result indicates the presence of the parasite but does not necessarily indicate that it is the cause of any symptoms. Some strains of protozoa are nonpathogenic, and some helminths cause little or no illness.
Clinical Reference
1. Garcia LS. Diagnostic Medical Parasitology. 6th ed. AMS Press; 2016
2. Shane AL, Mody RK, Crump JA, et al. 2017 Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea. Clin Infect Dis. 2017;65(12):e45-e80. doi:10.1093/cid/cix669
Day(s) Performed
Monday through Saturday
Report Available
4 to 6 daysTest Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
87177-Concentration (any type), for infectious agents
87209-Smear, primary source with interpretation; complex special stain (eg, trichrome, iron hematoxylin) for ova and parasites
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
OPE | Ova and Parasite, Microscopy, F | 10704-5 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
OPE | Ova and Parasite, Microscopy, F | In Process |