Validated DNA Stool Testing & Tough Clinical Questions

Doctor’s Data GI360 Stool Test with Dr. David Quig.

Key Takeaways

  • The GI 360 stool test is highly validated and vetted.
  • Not all dysbiosis requires treatment: Consider the presentation of the patient along with test results.
  • Using culture and PCR-DNA analysis together provides better information than one alone.

Stool tests are a valuable clinical tool, but not all lab tests are created equally. I’ve been skeptical about the validity of several brands on the market.

I recently met with Dr. David Quig from Doctor’s Data to hear more about their new GI 360 stool test that blends PCR-DNA and stool culture-based testing.

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In This Episode

Dr. David Quig’s Background … 00:05:54
Dr. Quig’s Perspective on Stool Testing … 00:06:40
Culture vs. DNA Stool Testing … 00:09:44
False Positives … 00:11:45
Interpreting GI Pathogen Levels … 00:14:28
Interpreting Commensal Bacteria Results … 00:17:33
Doctor’s Data’s Culture Profile … 00:20:59
When PCR & Culture for Yeast Disagree … 00:23:00
What Requires Antimicrobial Treatment … 00:27:29
Does Blastocystis hominis Require Treatment? … 00:31:48
Interpreting Probiotic Species Levels … 00:34:16
GI 360 Test Result Description … 00:38:04
Peer Reviewed PCR Data … 00:45:14

Doctor’s Data GI 360 Stool Test

Stool tests look for bacteria in the stool, as well as other organisms, such as parasites and yeasts.

Dr. Quig said, “There’s no one perfect methodology for stool analysis…”. Doctor’s Data’s new GI 360 stool test aims to provide the best of both PCR-DNA testing and stool culture testing. These two different types of testing have different uses. Dr. Quig suggested that stool culture is “…like trolling a net behind a boat, where we can see what is there….[and] PCR is like only having 7 or 12 fishing lines out with different specific baits where you’re only going to answer the question, “Is it there?”

PCR-DNA testing is extremely sensitive, sometimes able to detect a single organism in a unit of sample.

Stool Culture testing can provide a broader picture of what’s present and at what level.

According to Dr. Quig, both types together give a much better picture of what’s truly going on.

Doctor’s Data’s Validated Culture Profile

The GI 360 uses the GA MAP data from a research group in Norway to analyze the gut microbiome composition, and to evaluate it for dysbiosis. These data “…have been validated and tested in almost 50 different clinical trials to be most predictive and associated with dysbiosis.” Additionally, the two different PCR platforms Doctor’s Data uses in its testing have been evaluated in 20 peer-reviewed clinical trials, on topics from fecal microbiota transplant (FMT) to IBS (irritable bowel syndrome).

GI 360 Test Result Description

The GI 360 reports on two main areas:

  • Dysbiosis of non-pathogenic species. A result three or greater [represents] worsening degrees of dysbiosis.
  • Pathogenic dysbiosis that may need to be addressed, such as Salmonella, H. pylori, or Candida. Not all pathogenic results require treatment. 

Interpreting Stool Tests

How you interpret a stool test is key to using this important tool correctly. I asked Dr. Quig several questions to help flesh out what the various results mean clinically.

False Positives

I asked Dr. Quig if false positives were possible and how he recommends reading the test data to protect against this. Dr. Quig said, “If you’re using highly standardized PCR testing, you really don’t get false positives in the sense that the test is wrong…however, that [result] may be residual DNA left over from a pathogenic bacterial infection or a viral infection that occurred symptomatically three to six weeks ago. So…it’s a false positive in the sense that the clinical symptoms may not be consistent. “False positives” are just a matter of clinicians being educated about how to interpret that.”

Pathogenic Bacteria Results

With the pathogens screened on the GI 360 test, “there is no clinically acceptable level.” If they are present at any level, this is usually an indication that treatment is necessary.

Commensal Bacterial Overgrowth Results

Many bacterial species are considered a normal part of the microbiome, but when overgrown are a sign of dysbiosis. Dr. Quig noted, “We have those opportunists [where] an abundance…is really just a confirmation of a disruption of a healthy microbiome.”

Probiotic Bacteria Results

If by PCR you’re seeing extremely low deviation from normal with Lactobacillus or Bifidobacterium, that patient will likely benefit from a Lacto-Bifido combo type of probiotic.

When PCR & Culture for Yeast Disagree

I asked Dr. Quig what he would recommend to clinicians when a yeast culture doesn’t agree with the microscopy. He outlined two different possibilities:

  • Positive microscopy with a negative culture could indicate SIFO (small intestinal fungal overgrowth)
  • Positive microscopy with a positive culture for beneficial yeasts could also indicate SIFO

He commented, “We use the microscopy to back up the culture…if there’s clinical symptoms of small intestinal fungal overgrowth, and moderate-to-many yeast by microscopy, but not culture, the prevailing thought is that that’s an indication that there are yeast high in the GI tract, but they [won’t] be viable in culture when we get the stool specimen.”

SInce there is yet to be reliable testing for small intestinal fungal overgrowth, this may help provide guidance for clinicians.

Sponsored Resources

Hi everyone. I want to thank Doctor’s Data who helped to make this podcast possible and who I’m very excited to say has now released a profile called the GI 360 which is finally a validated microbiota mapping measure.

ddi logo centered 2col 300

If you remember back, I’ve discussed numerous times the only lab that is really validating a mapping of the microbiota to have clinical significance is the GA map out of Norway. Well, turns out that Doctor’s Data is not only using the same methodology but also in collaboration with this group in Norway using their parameters to adjust what we call normal, abnormal or dysbiotic and normal. So great news, we finally have a validated measure.

Now this test also offers, in addition to the microbiota dysbiosis index, a PCR assessment for bacteria, virus and pathogens, a comprehensive microscopy for a parasite, a MALDI-TOF bacteria and yeast culture. And as you would imagine, because of the rigorous validation they’ve gone through, they also have approval from the CE, which is equivalent to the European FDA.
So great test, please check them out. Doctor’s Data is offering 50% off a practitioner’s first GI 360 test kit. Go to to claim your first kit, limit one per provider. The offer ends October 31st, 2020.

What Stool Test Results Require Antimicrobial Treatment?

One of the most-asked questions about stool test results is whether they show the need for treatment. According to Dr. Quig, the stool test findings don’t always require antimicrobial treatment. “There’s really two schools of thought. Some people like to get rid of something right away…The other approach is…to get things back into balance and work on restoring the health and abundance and diversity within the microbial community. I am a strong believer in restoring balance.”

Dr. Quig agreed with the idea of focusing on a holistic ecosystem approach, like I describe in Healthy Gut, Healthy You.

Does Blastocystis hominis Require Treatment?

There’s a lot of scientific debate about whether or not the unicellular parasite Blastocystis hominis is pathogenic or commensal. Dr. Quig said it comes down to the specific strain, and “You really have to…consider the presentation of the patient because there are many people in the microbiome world that feel that Blastocystis can be very much a commensal bacteria.”

The Bottom Line

The GI 360 is a highly validated stool test, offering an assessment of dysbiosis and pathogenic bacteria in your gut.

Doctor’s Data is offering 50% off of a practitioner’s first GI 360 kit. Go to to claim your first kit, limit one per provider. This offer ends October 31st, 2020.

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