Do I Need a Stool Test?
Exploring one of the hottest areas in diagnostic technology.
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 you hope nobody spills. You hear testing like that done all the time. 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, their actual problem was with their intestines, not their ego.
In its most conventional form, stool testing detects blood, Inflammatory Bowel Disease markers, and serious pathogens, such as bacteria, viruses, parasites, or worms. Then there’s stool testing used as a screening tool for colon cancer. All that has its place, but that’s not the stool testing we’ll discuss today. Today, we will 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, nasty 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) also runs stool testing.
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 don’t like nuances and want the basic idea, skip to the next heading. Stay with me if you love nuances and want a deep understanding of the differences.
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 will only report if something is positive or negative based on acute diseases. Labcorp also runs a basic stool culture that only detects the presence of bacteria, not viruses, yeast, or parasites.
Okay, what does that mean? Let’s take Salmonella, a definite pathogen. You eat some onions 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. That makes sense, right?
Let’s say you’ve had diarrhea and constipation for 6 months. There wasn’t a particular event you could 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 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 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. Consider 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 feel better?
Clinical Response
Of course, you might want to have a stool test run to figure out what’s wrong with you, start treatment, and start to feel better. But what if you didn’t need the test results 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.
Generally, a test should be used if the clinician feels it will change their clinical decision-making. If the clinician will recommend probiotics and digestive enzymes regardless of the test findings, why even run the test in the first place?
Besides, stool testing has several pitfalls, namely false positives. As it sounds, you get results that come back with a positive for H. Pylori. In some people, H. Pylori could 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 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 the testing necessary to save you time and money, check out The HIVE Natural Health Center and head 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.
