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HelpTest ID OAP Parasitic Examination
Useful For
Detection and identification of parasitic protozoa and the eggs and larvae of parasitic helminths
Testing Algorithm
The following algorithms are available in Special Instructions:
-Parasitic Investigation of Stool Specimens Algorithm
-Laboratory Testing for Infectious Causes of Diarrhea
Special Instructions
Method Name
Microscopic
Includes concentrated wet preparation and permanent (trichrome) stained preparation. Also includes exam for fecal leukocytes.
Reporting Name
Parasitic ExaminationSpecimen Type
FecalMicrobiology Test Request Form (T244) (http://www.mayomedicallaboratories.com/it-mmfiles/microbiology_test_request_form.pdf)
General Test Request Form (T239) (http://www.mayomedicallaboratories.com/it-mmfiles/general-request-form.pdf)
Specimen Type: Stool, duodenal aspirate, colonic washing, liver fluid/abscess
Container/Tube: ECOFIX preservative (Supply T219)
Specimen Volume: Portion of stool; or entire collection of intestinal specimen or liver fluid/abscess
Collection Instructions:
1. Place specimen into preservative within 30 minutes of passage or collection.
2. Follow instructions on the container as follows:
a. Mix the contents of the tube with the spoon, twist the cap tightly closed, and shake vigorously until the contents are well mixed. Refer to the fill line on the Ecofix vial for stool specimens.
b. Do not fill above the line indicated on the container.
Specimen Type: Respiratory specimens or tissue
Sources: Bronchial washing, sputum, bronchoalveolar lavage
Container/Tube: Sterile container
Specimen Volume: Entire collection
Collection Instructions:
1. Place specimen into container and send refrigerate.
2. Specify on the order if a specific parasite is suspected.
Additional Information:
1. It is strongly recommended that multiple stool specimens be submitted for ova and parasite analysis. At least 3 specimens should be collected, 1 each day or on alternate days (over a maximum 10-day period). Parasites are shed irregularly in stool and examination of a single specimen does not guarantee detection.
2. To submit worms or worm segments, place in 70% alcohol and order PARID / Parasite Identification instead of the OAP / Parasitic Examination.
a. If Cryptosporidium is suspected, order CRYPS / Cryptosporidium Antigen, Feces instead.
b. If Giardia is suspected, order GIAR / Giardia Antigen, Feces instead.
c. If Cyclospora is suspected, order CYCL / Cyclospora Stain instead.
d. If microsporidia are suspected, order MTBS / Microsporidia Stain instead.
e. If pinworm is suspected, order PINW / Pinworm Exam, Perianal instead. Perianal skin sampling using clear cellophane tape or a SWUBE device is required for this test.
3. If the sources is something other than listed in Specimen Required:
a. Urine-send for SHUR / Schistosoma Exam, Urine or TVRNA / Trichomonas vaginalis by Nucleic Acid Amplification as applicable
b. Skin scrapings-send for PARID / Parasite Identification if scabies is suspected
c. Corneal scrapings/biopsy, CSF, or brain tissue for free-living amebae (Acanthamoeba or Naegleria)-send for ACANT / Acanthamoeba/Naegleria species, Corneal Scraping or Spinal Fluid
Specimen Minimum Volume
5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Fecal | Ambient (preferred) | 21 days |
| Refrigerated | 21 days |
Clinical Information
A variety of different parasites may be found in stool specimens, duodenal aspirates, respiratory specimens, liver cyst aspirates/abscesses and tissues. 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 stool 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 the stool parasitic exam is the appropriate test for their detection. See Parasitic Investigation of Stool Specimens Algorithm in Special Instructions for determining which test should be ordered based on the patient’s exposure history and risk factors.
Reference Values
Negative
If positive, organism identified
Cautions
If stool specimens are suspected of containing tapeworm segments or other adult worms, the suspected worm should be placed in 70% alcohol and submitted for PARID / Parasite Identification.
For optimal results, the specific test should be ordered for detection of Giardia, Cryptosporidium, microsporidia, Cyclospora, or pinworm.
This test is not appropriate for the detection of Acanthamoeba, Naegleria, microfilariae, malaria, trypanosomes, Toxoplasma, or Trichomonas.
Parasitic examination of a minimum of 3 stool specimens is required for the detection of ≥90% of some protozoal infections.
Parasitic infections are uncommonly acquired in the hospital setting. This test is not usually useful in patients hospitalized for more than 3 days.
Day(s) Performed
Monday through Friday; 8 a.m.-7 p.m., Saturday; 8 a.m.-4 p.m.
Report Available
2 daysPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test uses a standard method. Its performance characteristics were determined 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