Focus On: Gastrointestinal-Microbial Assay Plus (GI-MAP)
The GI-MAP™ utilises cutting-edge FDA-approved technology to provide a true DNA-based assessment of a patient's gut microbiome from a single stool sample. This arms the clinician with actionable information on microbes that are well-researched to cause disease or disrupt normal microbial balance and contribute to many inflammatory, autoimmune, metabolic, cardiovascular, and other chronic diseases.
The GI-MAP™ is the sole focus of Diagnostic Solutions Laboratory, allowing them to become leaders in gut microbiome testing.
What Makes The GI-MAP™ Different?
- Automated, multiplex PCR analysis method, allowing for the simultaneous measurement of multiple bacteria, fungi, parasites, and viruses (more info below)
- Single stool sample
- DNA sequencing of 16S and 23S rRNA allows for superior sensitivity and specificity in the detection of 15 of the most common causes of gastroenteritis, as well as other chronic diseases
- H. pylori is measured with virulence factors
- Intestinal health markers allow for a comprehensive analysis of your gut microbiome, together with markers of inflammation, mucosal immune system and digestion
- Quantitative and qualitative analysis providing superior clarity to results
- Evidence-based and transparent: all data available in the fully-referenced 26-page White Paper.
What Advantage Does The GI-MAP™ Offer?
In the last few decades, DNA analysis has transformed the field of microbiology. Culture techniques - previously the standard - leave up to 50% of bacterial species virtually invisible.
For instance, anaerobic bacteria make up a large part of the human gut microbiome and can be opportunistic and cause illness, therefore, inability to cultivate these organisms left a large blind spot for clinicians and patient's when trying to diagnose the source of infection.
What's the difference between Multiplex Polymerase Chain Reaction (PCR) and Culture Techniques?
Multiplex PCR makes it possible to simultaneously detect many different organisms in one sample. The automated nature of this method minimises the chance for human error; indeed, this is the only FDA-cleared DNA test for gastrointestinal microbes and pathogens available.
Multiplex polymerase chain reaction (PCR) means that many genes are amplified at the same time, as though many separate PCR reactions were happening at once. This technique makes it possible to simultaneously detect many different organisms in one sample. Multiple primers and probes for each organism allow for enhanced sensitivity and specificity. The method measures the 16S or 23S ribosomal RNA (rRNA) regions, virulence factors, and viral targets for microbial detection.
Other stool tests on the market primarily rely on bacterial culture of the stool specimen. A limitation of this method is that only the organisms that grow can be identified, meaning anaerobic organisms and parasites that do not grow under routine culture conditions cannot be identified. This is particularly prevalent with anaerobes like Lactobacillus. Often results of 'NG' or '0+' are reported, but it obviously does not mean it is not present, just simply that it would not grow in the lab, which is also seen with many yeasts and fungi.
A further limitation comes with sensitivity and specificity. The GI-MAP™ reports organisms as <dl (less than detectable limit). This means that there are less than 100 cells per gram for the organism. It does not mean that the stool sample was necessarily void of that organism, but most bacteria need to be present in higher numbers to cause dysbiosis or disease.
In contrast, when culturing bacteria, if there is close to 100 cells per gram it could be reported as positive. This is because when streaking the agar plates, the sample is spread into 4 areas of the plate with slightly less sample in each. If there is growth into the 4th area, even of just a few cells, it is called 4+. Some samples may have 70 cells per gram grow in the 4th quadrant and get reported as 4+ and others may have 10,000 cells per gram and they would also be 4+.
Hence, collection of stool specimens for DNA analysis most closely represents the actual microbial populations of the patient’s gastrointestinal tract at the time of collection versus culture based methods. This is why it is the methodology of choice for microbiome researchers and now - via Diagnostic Laboratory - to Functional and Integrative Medicine practitioners for better patient outcomes.