Gut microbiome testing and international scientific consensus
Gut microbiome testing and international scientific consensus
International guidance on gut microbiome testing is still evolving, but it is already shaping how microbiome reports, laboratory workflows, and consumer-facing interpretations should be presented. This article explains the basics of gut microbiome testing, including 16S amplicon sequencing, what the method can and cannot tell you, and how InnerBuddies aligns with key points from the international scientific consensus statement on microbiome testing in clinical practice.
Key takeaways
- 16S amplicon sequencing is a marker-based method used to profile bacteria in stool samples.
- The method can show taxonomic composition, relative abundance, and diversity metrics, but it has resolution limits.
- 16S amplicon sequencing is closely related to metabarcoding; in many contexts, the terms overlap.
- Good microbiome testing depends on careful sample collection standards, validated analysis pipelines, and cautious report interpretation.
- InnerBuddies focuses on transparent, science-based microbiome reporting and avoids unsupported claims.
What do the main terms mean?
Gut microbiome testing usually refers to analyzing stool DNA to understand which microbes are present and how they are distributed. A common approach is 16S amplicon sequencing, which targets a specific region of bacterial DNA rather than sequencing the entire genome. This makes it useful for community profiling, especially when the goal is to understand broad bacterial composition.
Microbiome report interpretation should be careful and evidence-based. Because microbiome science is still developing, reports should describe what the data can support and avoid overstating clinical meaning.
Quick answers to common questions
What is 16S amplicon sequencing?
It is a DNA sequencing method that targets the 16S ribosomal RNA gene in bacteria. It helps identify and compare bacterial groups in a sample.
In practice, it is widely used for gut microbiome testing because it provides a structured overview of bacterial community composition at a reasonable cost.
What does amplicon sequencing tell you?
It can show which bacterial taxa are present, their relative abundance, and diversity metrics such as richness and evenness.
It does not provide a full genome view, and it has limits in species- or strain-level resolution depending on the method and database used.
Is 16S amplicon sequencing metabarcoding?
Yes, 16S sequencing is generally considered a form of metabarcoding.
Metabarcoding means using a short genetic marker to identify organisms in a mixed sample. The 16S marker is commonly used for bacterial profiling.
How does InnerBuddies compare to scientific consensus?
InnerBuddies aligns with many of the practical recommendations in the international consensus statement, including sample handling, accredited lab processing, validated analysis steps, and transparent reporting.
The article below explains these areas in more detail and also notes where the evidence base is still limited for clinical use.
Why are international guidelines important for gut microbiome testing?
On December 5, 2024, an international group of microbiology scientists published a consensus statement on microbiome testing in clinical practice in The Lancet (see link here). The goal was to outline good practice for microbiome testing as the field moves toward wider clinical and consumer use.
While evidence is still limited for many clinical applications, the consensus statement is useful because it highlights what a trustworthy microbiome test should do well: use high-quality laboratory methods, report results clearly, and avoid overclaiming.
How InnerBuddies compares with the international consensus
InnerBuddies is a science-driven company and a spin-off from Maastricht University. We review our workflows against current scientific guidance so that our product remains aligned with best practice as the field develops.
The consensus statement contains 35 recommendations across five working groups. InnerBuddies fully meets most of them and is partly compliant with the remaining items, especially where evidence is still evolving or where future clinical products would require different validation.
Working group 1: General principles and minimum requirements
Transparent, scientific communication
Microbiome testing should be described in a way that is reliable, transparent, and realistic about its current limits in clinical practice. InnerBuddies focuses on communicating the purpose of the test clearly and translating scientific language into consumer-friendly language.
We also keep the current product focused on healthy populations and general wellness topics rather than specific medical indications, because evidence for disease-specific use is still limited.
Multidisciplinary expertise
Microbiome testing involves sample handling, sequencing, data analysis, and report interpretation. InnerBuddies combines expertise from microbiology, nutrition, and AI/data analysis to support this workflow.
Clinical management should remain with health professionals
Any change in clinical management should be made by a referring physician or healthcare professional. InnerBuddies separates consumer use from healthcare professional use and does not position the current product as a diagnostic tool for specific conditions.
Accredited laboratories and data protection
InnerBuddies uses external laboratories that meet quality standards and are accredited and regulated. GDPR processing agreements are in place to support data protection.
Validated computational pipelines
Validated, up-to-date bioinformatics pipelines are essential for taxonomic profiling. InnerBuddies uses tested workflows and the SILVA database for microbial taxonomy assignment. The goal is to improve accuracy and make the analysis reproducible and transparent.
Working group 2: Procedural steps before testing
Testing should not replace clinical judgment
The consensus statement discourages direct patient requests for microbiome testing without clinical context when the intended use is medical. InnerBuddies therefore distinguishes between general consumer testing and healthcare professional-guided use.
Relevant background data should be collected
Before testing, it is useful to collect information that may influence microbiome patterns, such as age, sex, BMI, dietary habits, smoking, alcohol use, bowel habits, medications, and medical history. InnerBuddies includes a questionnaire covering these areas so the report can be interpreted in context.
Do not change your routine before testing unless advised
The test should generally reflect a typical baseline. InnerBuddies does not advise users to change diet or stop therapies before sampling unless a healthcare professional recommends it.
Stool sample collection standards
Good stool sample collection standards help reduce contamination and preserve microbial DNA. InnerBuddies includes kit materials designed to make collection easier and to help keep the sample stable during transport.
The collection tube contains buffer fluid intended to support sample stability for an extended period, and the laboratories store samples under appropriate conditions after arrival.
Working group 3: Microbiome analysis
16S amplicon sequencing data analysis step by step
16S amplicon sequencing data analysis usually follows several key steps:
- Preprocessing and quality filtering — remove primers, trim low-quality regions, and filter out reads that are too short, too long, or otherwise low quality.
- Chimera filtering — remove sequences that are likely artefacts of PCR amplification.
- ASV or OTU inference — group sequences into amplicon sequence variants (ASVs) or operational taxonomic units (OTUs), depending on the pipeline used.
- Taxonomy assignment — match cleaned sequences to a reference database such as SILVA to estimate bacterial identity.
- Diversity analysis — calculate alpha diversity and beta diversity outputs for interpretation.
- Reporting — present taxa, relative abundance, and interpretation in a user-friendly format.
InnerBuddies uses preprocessing and filtering steps before analysis, including primer removal, quality filtering, length filtering, and chimera filtering.
What does amplicon sequencing tell you?
Amplicon sequencing is useful for profiling microbial communities. In a gut microbiome report, it can help show:
- Taxonomic composition — which bacterial groups are detected in the stool sample
- Relative abundance — how much of each detected taxon is present compared with the others
- Diversity metrics — measures such as richness and evenness
- Comparison patterns — how a sample relates to a reference cohort or expected range
Important limitations should also be stated clearly. Marker-based methods do not provide full-genome resolution, and the apparent result can be influenced by PCR bias, primer choice, database coverage, and the level at which bacteria can be confidently assigned.
InnerBuddies sequencing approach
InnerBuddies currently uses 16S amplicon sequencing for gut microbiome profiling. Depending on the platform, this may involve the V3/V4 region on Illumina MiSeq or full-length 16S sequencing on Oxford Nanopore. We also continue to explore other sequencing approaches in research settings.
Alpha diversity and beta diversity
Microbiome analysis should include both alpha diversity and beta diversity outputs when possible. Alpha diversity describes diversity within a sample, while beta diversity compares a sample with a reference or other samples.
InnerBuddies reports alpha diversity metrics such as Shannon diversity, evenness, and richness. We also compare results with a healthy cohort so users can understand their profile in relation to a reference population.
Taxonomic profiling and reference cohorts
A complete taxonomic profile is an essential part of microbiome testing. InnerBuddies provides taxonomic reporting and allows users to download data from the portal. We also compare key taxa with a healthy cohort to support interpretation, while avoiding overly rigid species-level reference ranges where evidence is insufficient.
Longitudinal testing
Repeated testing over time can be useful in some contexts because microbiome patterns may shift. InnerBuddies supports multiple tests and comparison over time, which can help users and healthcare professionals observe changes in the profile.
Functional or metabolic interpretation should be cautious
Metabolomic analysis of biofluids and direct inference of clinical outcomes from microbiome data are not recommended without strong evidence. InnerBuddies therefore treats functional interpretation cautiously and continues to base consumer-facing reporting on what can be supported by the available data.
Working group 4: Characteristics of reports
Clear report design
A microbiome report should be easy to understand. User-friendly charts, bar plots, and clear summaries are preferable to overly technical visualizations. InnerBuddies uses infographic-style visualizations to show how key bacteria compare with healthy ranges.
Deepest possible taxonomic resolution
Results should be reported at the deepest taxonomic resolution that can be supported reliably. InnerBuddies reports genus-level resolution for Illumina MiSeq 16S V3/V4 and species-level resolution for full-length 16S sequencing where appropriate. We avoid strain-level claims when the method does not support them reliably.
What should not be overemphasized?
Some popular metrics, such as the Firmicutes-to-Bacteroidetes ratio or a single dysbiosis score, are not recommended as definitive markers of gut health. InnerBuddies does not rely on these shortcuts because they can oversimplify the data.
Personalized advice should stay evidence-based
The consensus statement is cautious about post-testing therapeutic advice. InnerBuddies provides personalized nutrition, food diary, and probiotic/prebiotic guidance, but these outputs are based on multiple inputs, including survey data and the food diary, and are intended to support healthy lifestyle choices rather than diagnose or treat disease.
Because probiotic effects can be strain-specific and context-dependent, advice should be interpreted carefully and not treated as medical treatment.
Raw data access
Users may request or download their available taxonomic data from the portal, which supports transparency and second-opinion review where appropriate.
Working group 5: Relevance in clinical practice now and in the future
At present, there is insufficient evidence to broadly recommend routine microbiome testing for many clinical use cases. At the same time, research continues to expand, and future dedicated studies may clarify where microbiome profiling is helpful.
InnerBuddies is involved in ongoing research collaborations and aims to keep its platform aligned with future evidence as it develops.
FAQ
Is 16S amplicon sequencing the same as 16S rRNA sequencing?
They are closely related terms. In practice, both usually refer to sequencing a targeted 16S bacterial marker region to profile microbial communities.
Is amplicon sequencing only used for bacteria?
No. Amplicon sequencing can be used for different organisms depending on the marker region, but 16S is most commonly used for bacteria in gut microbiome testing.
Can 16S sequencing identify every microbe in the gut?
No. It is a marker-based approach, so it gives useful bacterial community information but not a complete picture of every organism or every gene in the microbiome.
Why does the database matter in microbiome testing?
Taxonomy assignment depends on the reference database. A validated database such as SILVA helps improve consistency, but no database removes all uncertainty from marker-based profiling.
Can microbiome testing diagnose disease?
Current consumer microbiome tests should not be used as standalone diagnostic tools. They may support education and general wellness insights, but diagnosis should always be handled by qualified healthcare professionals.
Final note
Gut microbiome testing is a fast-moving field, and international scientific consensus is helping define what high-quality testing should look like. InnerBuddies aims to follow those principles by using accredited labs, validated sequencing workflows, cautious interpretation, and transparent reporting. As the evidence base grows, the role of microbiome testing in clinical practice will likely become clearer.