Do I Need a Stool Test?

Exploring one of the hottest areas in diagnostic technology.

Photo by National Cancer Institute on Unsplash

At your typical doctor’s office or hospital you’ve likely seen x-ray devices, extensive MRI machines, phlebotomists drawing people’s blood, and tiny cups of seemingly yellow liquid that you hope nobody spills. You hear testing like that done all the time. Now what if someone told you they went #2 and put it in a bag to be shipped and delivered elsewhere? First, you’d think they had a problem with that person and wanted to pull a rude prank on them. However, the actual problem they were having was with their intestines, not their ego.

In its most conventional form, stool testing is used for the detection of blood, Inflammatory Bowel Disease markers, and serious pathogens, such as bacteria, viruses, parasites, or worms. Then there’s stool testing that’s used as a screening tool for colon cancer. All that has its place, but that’s not the stool testing we’ll be discussing today. Today, we’re going to discuss the merits of newer, “functional” stool and microbiome testing and hopefully answer your ultimate question, “Do I need a stool test?”

Does Newer Mean Better?

These newer stool tests assess for blood and serious pathogens, but they also can assess for digestive imbalances (pancreatic enzymes, undigested fat), microbial imbalances (normal bugs, bad bugs, “opportunistic” bugs), and markers of leaky gut. In order of clinical importance, in my opinion, the list includes: 1) Pathogen detections, 2) IBD markers, 3) microbial imbalances, 4) digestive health, and 5) leaky gut markers.

Typically, these newer tests are run by companies that aren’t as recognizable in the conventional space. Labcorp (one of the two biggest lab companies in the US along with Quest) runs stool testing as well.

Okay here’s a little heads up, I’m about to explain the differences in methodologies in stool tests, which can get very nuanced. If you’re not too much of a fan of nuances and just want the basic idea, skip to the next heading. If you love nuances and want a deep understanding of the differences, stay with me.

Labcorp uses PCR (Polymerase Chain Reaction) technology for its Gastrointestinal Profile, which detects very similar information to the newer stool testing companies. PCR is qualitative, meaning it’s only going to report if something is positive or negative based on acute diseases. Labcorp also runs a basic stool culture, but that only detects the presence of bacteria, not viruses, yeast, or parasites.

Okay what does that actually mean? Let’s take Salmonella, a definite pathogen. You eat some onions that are contaminated with Salmonella, get really sick, and then go to the doctor and have a stool test done. Using Labcorp testing, your labs come back “positive” for Salmonella. Makes sense, right?

Now, let’s say you’ve had diarrhea and constipation for 6 months. There wasn’t a particular event that you can pinpoint your digestive woes to, it just started happening. You go to your doctor, and they decide you to run a stool test from Labcorp, and your results come back “negative” for Salmonella. Negative” does not mean Salmonella isn’t present, it just means there wasn’t ENOUGH of it present to cause an acute disease.

There’s the rub. Normal PCR technology only tells you if something is present enough to cause acute illness. But in reality, you could have low levels of an organism that are contributing to your diarrhea and constipation. In comes the “functional” lab testing.

The GI-MAP from Diagnostic Solutions Laboratory uses qPCR. The “q” in qPCR stands for quantitative, meaning it will detect the actual amount of something present in a stool sample. Think of qualitative measurement (Labcorp) as a binary, yes or no, and quantitative measurements (GI-MAP) as detecting an absolute amount.

Which one is correct? Both. I know of clinicians who get great results using both types of testing. At the end of the day, does it really matter what test is “right” or whether you actually feel better?

Clinical Response

Of course, the main reason you might want to have a stool test run is to figure out what’s wrong with you, start treatment, and start to feel better. But what if you didn’t need the results of a test to start feeling better? What if you could start some validated, empirical therapies that could lead you down the path of gut healing.

Stool testing should be used after you’ve exhausted all the foundational gut supportive therapies such as diet, probiotics, enzymes, exercise, relationship with stress, etc. In general, a test should be used if the clinician feels like it’s going to change their clinical decision-making. If the clinician is going to recommend probiotics and digestive enzymes regardless of the test findings, why even run the test in the first place?

Besides, there are also several pitfalls to stool testing, namely false positives. As it sounds, you get results back, and it comes back with a positive for H. Pylori. In some people, H. Pylori could actually be normal for them to have. In this context, stool tests can create a lot of “noise” that could send you down rabbit holes that aren’t actually relevant. This is where it takes the skills of a good clinician who can interpret the lab results objectively and in the context of the person’s symptoms. I’ve also seen several people with completely “normal” lab findings, even from the functional labs, who are in obvious digestive distress. Again, if this person hasn’t tried foundational gut therapies, it might be worthwhile to start there.

If you’re looking for a clinician who understands the practical nuances and application of stool testing and will only use testing that’s necessary in order to save you time and money, check out The HIVE Natural Health Center and head on over to our Functional Medicine page.

As always, Trust in Your Gut.

Disclaimer: The contents of this article are for educational purposes only, and are not intended to diagnose or treat any condition. Do not apply any of the information in this article without first speaking with your doctor.

Helping fitness enthusiasts optimize their gut health. Doctor of Chiropractic. Instagram: @drnickbelden. LinkedIn: Nicholas Belden