Stool ova and parasites exam

Stool Ova and Parasite Exam

A Stool ova and parasite exam (O&P) is a laboratory test used to detect the presence of parasites and their eggs (ova) in a stool sample. This exam helps diagnose parasitic infections and can help monitor successful treatment of such infections. It looks for evidence of parasitic disease, which includes protozoa and helminths.

Purpose of the Test

A stool ova and parasite exam is commonly used to detect an active intestinal parasite infection. It is often used in combination with other laboratory tests to assess intestinal health. The exam is also frequently used to inspect the gastrointestinal tract for evidence of parasitic infection after testing shows poor nutrition, diarrhea, or anemia.

Preparation for Test

There is no special preparation needed for a stool ova and parasite examination. You should not take antibiotics within two weeks prior to the exam so as not to interfere with the results.


To perform the test, fresh stool is placed onto a microscopic slide. The slide is then inspected visually under the microscope. At the same time a special stain is added to the sample to highlight any parasites or their eggs. Other staining techniques may also be used, depending on the type of organism being looked for.

Types of Parasites Tested for in Exam

The types of parasites examined include:

  • Protozoa
  • Tapeworms
  • Hookworms
  • Pinworms
  • Roundworms
  • Giardia
  • Cryptosporidium

Risks Involved in Exam

The risks associated with a stool ova and parasite examination are minimal. However, improper handling of the sample can lead to a false-positive result.

Why and When the Exam is Performed?

The stool ova and parasite exam is performed when a doctor suspects a parasitic infection. It is most commonly performed in people with symptoms such as abdominal pain, weight loss, bloody stools, and diarrhea. It may also be performed when a person has recently traveled to an area where parasitic infections are common.