Ova and Parasite Exam

This is a microscopic exam of your stool to determine whether you have a parasite infecting your gastrointestinal tract. It is sometimes done if you have diarrhea that lasts more than a few days and/or have blood or mucus in your loose stools, especially if you drank stream or lake water. Most people who are infected by parasites become infected by drinking water or eating food that has been contaminated with the ova. This contamination cannot be seen - the food and water will look, smell, and taste completely normal. The most common parasites are three single cell parasites: Giardia lamblia, Entamoeba histolytica (E. histolytica), and Cryptosporidium parvum. They are found in mountain streams and lakes throughout the world and may infect swimming pools, hot tubs, and occasionally community water supplies.


A fresh stool sample is collected in a clean container (or on a clean surface). The stool sample should not be contaminated with urine or water. Once it has been collected the stool is usually taken to the laboratory within about an hour after collection, or is transferred into bottles containing different preservative solutions.

Once the stool has been preserved, it should be returned to the laboratory within a day or so. If your caregiver has ordered multiple samples, you may collect and transfer all of the stool samples into preservative bottles before returning them to the laboratory. When multiple samples are ordered, they are collected at different times, often on different days. The bottles should be labeled with the patient's name and the date and time of the stool collection.


Your stool specimen should test negative for ova and parasites.

Ranges for normal findings may vary among different laboratories and hospitals. You should always check with your doctor after having lab work or other tests done to discuss the meaning of your test results and whether your values are considered within normal limits.


Your caregiver will go over the test results with you and discuss the importance and meaning of your results, as well as treatment options and the need for additional tests if necessary.


It is your responsibility to obtain your test results. Ask the lab or department performing the test when and how you will get your results.