Colonoscopy and Endoscopy Parasite Test

Endoscopies and colonoscopies can sometimes find parasitic worms like roundworms and tapeworms. This test can occasionally find intestinal flukes.

But, because many intestinal parasites can't be detected with this test, I would not recommend this as a comprehensive parasite test.

How does this test detect parasitic worms?

During an endoscopy, a fiber optic cable with a camera at the end will be inserted into your mouth, down your esophagus, through your stomach, and then into your small intestines. So an endoscopy can find parasites that are large enough to see the naked eye, and are present in the small intestines.

During a colonoscopy, a fiber optic cable with a camera at the end will be inserted up your rectum, into your colon or large intestines. A colonoscopy can find parasites in your colon that are large enough to see without magnification.

Can an endoscopy or colonoscopy find intestinal worms?

The main class of parasites this test can detect are parasitic worms. Intestinal flukes could theoretically be discovered by the gastroenterologist - but probably won't be seen.

In best case scenarios, it is possible that the following parasites can be detected. But, I will explain below, how these worm parasites can be missed even if you are infected with them! Scary I know...

Here's a full list of parasites that may be found by this test:

  • Roundworms
    • Ascaris lumbricoides
    • Hookworms
    • Human whipworm
  • Flukes
    • Chinese liver fluke
    • Human liver fluke
    • blood fluke
  • Tapeworms
    • pork tapeworm
    • fish tapeworm

What parasites will an endoscopy/colonoscopy miss?

I really need to emphasize that this is not a great test for detecting worms, and will always miss microscopic parasites.

This test can miss parasitic worms

There are 2 reasons why an extremely skilled doctor can miss parasitic worms...and it comes down to the parasitic life cycle.

  1. All parasitic worms may be dead and missing from your intestines - but their eggs may still be present in your intestines. The eggs will soon hatch and then begin the parasites life cycle. These eggs are microscopic, and aren't visible with the camera used in a colonoscopy or endoscopy. So the parasitic worm infection will be missed in this case.
  2. Parasitic worms spend part of their life cycle outside the intestines. Below I show the life cycle of the worm Ascaris lumbricoides. And you can see that that parasite spends part of it's life cycle in your lungs. And if your endoscopy happens when your doctor is doing the endoscopy, then your doctor will miss the ascaris infection.

This test will miss all microscopic parasites

Many parasites are microscopic. Because the camera doesn't doesn't have much magnification (if any) - then it will miss all microscopic parasites. Here's a list of the parasites that will be missed by this test:

  • Protozoa
    • Entamoeba Histolytica
    • Cryptosporidium
    • Giardia lambilia
    • Blastocystis hominis

Overall effectiveness of this test for finding parasites

To summarize and simplify, here is what this parasite test can find:

  • can sometimes find parasitic worms
  • can rarely find intestinal flukes
  • can not detect microscopic parasites

So based on the above facts, this is an unreliable parasite test that I would not recommend.

That being said, often times people get a colonoscopy to diagnose irritable bowel disease, so the discovery of parasites in the colon is incidental.

This is not a good parasite test. There are better tests out there.

If you're serious about getting a proper intestinal parasite test, then stick with the parasite stool test.

The benefits of this test are:

  • Detects parasitic worms
  • Detects microscopic parasites
  • Test can be administered at home

To see the 6 most common parasite tests compared, click here.

Questions about parasite testing?

Evan Jerkunica,'s founder is happy to help. To get your questions answered, you can:

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