Blood and lab tests
What Does Stool Ova and Parasites (O&P) Mean?
Stool ova and parasites · say it: STOOL OH-vuh and PAIR-uh-sitesAlso written: O&P, ova, cysts and parasites, OCP, stool parasite test, faecal ova and parasites
Short answer
A stool ova and parasites test looks at a poo sample under a microscope for parasite eggs (ova), cysts and the parasites themselves.
What it means
Ova means eggs. In this test, a lab examines a small amount of stool under a microscope, looking for the eggs of worms, the cysts of tiny one-celled parasites such as Giardia, and the parasites themselves. Some labs also use antigen or DNA tests on the same sample.
A doctor usually orders it for diarrhea that lasts more than a few days, stomach symptoms after travel, or unexplained changes in some blood results. Parasites do not shed eggs into every bowel movement, so you may be asked to collect two or three samples on different days. The report lists anything the lab found, or states that none was seen.
This test is different from a stool culture, which grows bacteria, and from a fecal occult blood test, which looks for hidden blood. One sample can be sent for several of these tests at once.
Where you may see it
- Microbiology reports headed 'Stool O&P' or 'Ova, cysts and parasites'
- Lab request forms for diarrhea after travel abroad
- Results portals listing each of several samples collected on different days
📄 How it looks on a report
Stool O&P (specimen 2 of 3): No ova, cysts or parasites seen.
🙅 What it does not mean
- A single 'none seen' result does not always rule out a parasite, which is why labs often ask for more than one sample.
- Finding a parasite does not mean you were unclean. Many are picked up from water, food or soil, including while travelling.
- Some organisms named on the report are harmless passengers in the gut, so a finding is not always the cause of your symptoms.
🗒️ Questions to ask your doctor
🧾 Reports where you will see “Stool ova and parasites”
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🔗 Read more from trusted sources
- “Stool ova and parasites” on MedlinePlus ↗
US National Library of Medicine
- MedlinePlus lab test guides ↗
US National Library of Medicine
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General information about a medical word, not advice about your own results. Ask the clinician who ordered the test what it means for you.