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  • Writer's pictureGavin Guard, Medical Director

Gut health tests- are they worth it?

Updated: Jan 23, 2022

Key Takeaways

  • Many new tests claiming to assess gut health are not clinically relevant

  • We should rather stick to more validated tests such as blood chemistry


I recently came across an ad for a gut testing company. They claimed to have the “missing piece” of information to your gut health. Are they on to something or are they misleading the consumer? What are the best ways to assess your gut health? Stay tuned to find out.

Do popular gut tests live up to the hype?

In this article, I review the most popular functional gut tests. For each test, I give my rating of cost and usefulness.

Breath testing

Cost: $$$ ($199)

Usefulness: 3 out of 5 stars

A recent revelation in the field of gut research is the use of breath testing. This test entails drinking a sugar solution (glucose or lactulose) and then measuring the gas produced by the bacteria in our gut that gets absorbed into our blood, and eventually exhaled through our lungs.

In general, a higher amount of gas indicates the possibility of a condition called Small Intestinal Bacterial Overgrowth (SIBO). To read my full evaluation of breath testing and what SIBO is, check out this article.

However, there are a few problems with this test:

  1. No agreed upon consensus to what “SIBO positive” is

  2. No consensus of what the best sugar solution to use is

  3. Even the better glucose test only picks up on 50% of those with SIBO

  4. The breath test may not truly reflect a diagnosis of SIBO but rather, an altered microbiome.

In my practice, I don't use breath testing right out of the gate. Rather, I may use it in refractory cases to predict the patients who would benefit from an antimicrobial approach.


Cost: $$

Usefulness: 1 out of 5 stars

Our gut cells are “glued” together with proteins. It’s important for our gut cells to have a strong barrier to food fragments that can pass through these cells and activate our immune system. One such protein that holds these cells together is called zonulin. When our gut is damaged or inflamed, zonulin is released into the blood stream. We can then measure this in the blood.

the difference between a strong gut barrier and a "leaky gut"

Higher levels of zonulin are found in those with IBS. However, high levels are also found in those with no gut symptoms.

There still remains no consensus of how to use this test and how informative it truly is. In my practice, I do not use this test at all to inform my clinical decision making.

Microbiome tests

Cost: $$-$$$$

Usefulness: 0 out of 5 stars

Some tests aim to measure the many species of bacteria of your microbiome. They will then suggest replacing the missing or low levels of bacteria with specific probiotics. However, there is a lack of evidence to support this approach.

In fact, one popular stool test got in legal trouble after watch dog organizations found that the companies reference ranges were formulated from dog feces!

one popular microbiome lab used dog feces for its reference range

I have found no clinical utility in using these tests and I suggest you save your money by not buying these tests.

Best tests to assess gut health

Quantitative PCR stool test

Cost: $$$ ($179 with insurance)

Usefulness: 3 out of 5 stars

Popular tests such as GI-Map use targeted DNA sequences to identify and measure the quantity of specific bacteria, viruses, and parasites found in our stool. They do a fair job of detecting specific harmful microbes that we can direct treatment towards. One of the limitations is that it only assesses your large intestine (not your stomach or small intestine).

However, I rely more on their measurements of the following:

  • Steatocrit: this is a measurement of fat in your stool. A higher level could indicate problems with digesting and absorbing fat.

  • Elastase-1: a digestive enzyme produced and released by your pancreas. Lower levels indicate a condition called Exocrine Pancreas Insufficiency which necessitates the use of high-dose enzyme therapy.

  • Calprotectin: a good screening test for Inflammatory Bowel Disease (IBD) such as Crohn’s disease and Ulcerative Colitis.

I recommend working with a knowledgeable functional medicine clinician who is careful with your financial resources to help you decide which test is right for you.

Blood chemistry

Cost: $$

Practicality: 5 out of 5 stars

The one test I aim to do for all patients is a comprehensive blood panel. There is nothing fancy about this test but it’s the most validated way of getting an idea of overall health patterns including:

  • immune system function

  • inflammation

  • blood sugar control

  • iron balance

  • micronutrient status

  • anemia

  • liver function

  • kidney function

  • cholesterol health

  • hormonal balance

It’s important to get routine blood work that goes above and beyond the conventional few lab tests typically gotten on a routine physical. I believe it’s a crucial step in getting more information about your overall health and is the best way I can truly direct my treatment for patients.

The Bottom Line

There are a lot of promises claimed when it comes to these fancy gut tests. However, many of them fail to truly to a good job of assessing gut health. There are a few tests that I routinely use in clinical practice and that I feel like are validated markers. These include:

  • Steatocrit

  • Elastase-1

  • Calprotectin

  • Comprehensive blood panel (more than what is used in a routine physical)

Our clinic specializes in helping patients recapture their gut health and get back to a normal life where gas, diarrhea, constipation, and reflux don’t run their schedule. If you’d like a cost-effective and evidence-based approach to your gut health, then schedule a free 15-minute Free Health Strategy Session with us today.

I hope you found this information useful and helpful in your journey back to a healthier and happier life.

Like what you are reading? Learn more about how to take control of your health by signing up for the "5 Minute Health Makeover" below where I coach you through 3 pivotal strategies for better health.

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