# Microplastics Testing: Methods, QA/QC & Lab Results

> Understand microplastics testing standards, workflows & lab reports. The Wellness Quality Institute helps brands achieve defensible, credible results.

**Published:** 2026-08-21 | **Updated:** 2026-11-02 | **Author:** renatoloureiro
**URL:** https://www.wellnessqualityinstitute.com/articles/microplastics-testing-methodology-standards
**Type:** post

**Categories:** Certification

![Microplastics Testing: Methods, QA/QC & Lab Results](https://wellnessquality.sites.aigrowthagent.co/wp-content/uploads/sites/93/2026/08/1787131854548-224f28485858-1024x572.webp)

---

## Content

*Written by: Scott Steveson, Specialist, Wellness Quality Institute | Last updated: November 1, 2026*

## Key Takeaways

- Microplastics testing methodology standards govern how labs run tests. They do not govern what claims a result can support.
- Validated detection ranges begin at 20 µm for Raman or 50 µm for infrared. Current commercial methods do not measure the 1–20 µm fraction or any nanoplastics below 1 µm.
- Quality-control elements such as blanks, spike recoveries, replicates, chain of custody, and laboratory accreditation determine whether a dataset can support a defensible claim.
- Independent review of existing third-party lab data against a defined standard converts raw numbers into a claim that can withstand retailer or regulatory scrutiny.
- The Wellness Quality Institute provides independent verification of microplastics data through its Plastic-Free Pathway Verification program.

[Learn how The Wellness Quality Institute can verify your microplastics data.](https://www.wellnessqualityinstitute.com/?utm_term=microplastics-testing-methodology-standards&utm_campaign=ai_growth_agent)

## The Current Standards Map For Microplastics Testing

Microplastics testing uses several optional standards, each with a specific purpose and scope. Knowing what each standard covers, and what it leaves out, shows what your data can truly support.

**ISO 24187:2023** [sets general principles for analyzing microplastics in water, sediment, and living organisms](https://pmc.ncbi.nlm.nih.gov/articles/PMC13712325). It covers representative sampling, contamination control, sample preparation, particle-size classes, and how to choose an analytical method. It is a [horizontal framework, not a step-by-step test method](https://pmc.ncbi.nlm.nih.gov/articles/PMC13712325). It does not lock in a single instrument, extraction process, or lower particle-size limit. Any result under ISO 24187:2023 only applies to the particles that the chosen workflow actually collected and detected.

**ISO 5667-27:2025** [gives sampling guidance for suspended microplastics in domestic water, freshwater, seawater, treated wastewater, and untreated wastewater](https://standards.iteh.ai/catalog/standards/sist/2c3a07b3-ab99-416c-b54f-deca1c7b1bb4/sist-iso-5667-2026). It covers grab sampling, cascade filtration with multiple filters, and net sampling. It [explicitly excludes chemical analysis, biological methods, and digestion](https://standards.iteh.ai/catalog/standards/sist/2c3a07b3-ab99-416c-b54f-deca1c7b1bb4/sist-iso-5667-2026). It governs sampling only. The analytical method chosen after sampling controls the rest of the process.

**ISO 16094-2:2025** covers vibrational spectroscopy for microplastics in low-turbidity waters, including drinking water, and reports particle counts by size class across 1–5,000 µm for ten named polymers: polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polycarbonate (PC), polystyrene (PS), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), polyamide (PA), polymethyl methacrylate (PMMA), and polyurethane (PU). It can serve as an analytical reference when the method, matrix, lab validation, and equivalence are reviewed and accepted. It is not automatically interchangeable with the California State Water Board methods.

**ASTM D8332-20 and ASTM D8333-20** cover collection and preparation of water samples across drinking water, surface waters, wastewater influent and effluent, and marine waters for later identification and quantification by spectroscopic or pyrolysis methods. They are collection and preparation practices, not analytical methods, and they do not set a particle-size detection limit. The filter or sieve and the downstream technique define the size range.

**ASTM D8401-24** covers identification and quantification by pyrolysis gas chromatography/mass spectrometry (Py-GC/MS), which heats isolated material to 600 °C and identifies each polymer by marker compounds. It reports polymer mass, not particle counts or size distributions. It has no lower particle-size limit in the usual sense because mass, not size, is the constraint.

**California SWB-MP1-rev1** is the California State Water Resources Control Board’s infrared spectroscopy method for microplastics in drinking water. Its validated size range is greater than 50 µm through 5,000 µm.

**California SWB-MP2-rev1** is the Board’s Raman spectroscopy method. Its validated size range is greater than 20 µm through 5,000 µm.

**ISO/IEC 17025:2017** sets general requirements for the competence of testing and calibration laboratories. It is an accreditation foundation, not a test method.

California’s framework serves as a technical reference point for many organizations. No US federal microplastics testing standard exists. California did not create, approve, authorize, or endorse any private verification program, and alignment with its framework does not equal California approval. All of the standards above are optional tools that organizations may adopt.

For more detail on how these standards compare, see [Microplastics Testing Standards: ISO, ASTM & California](https://www.wellnessqualityinstitute.com/articles/microplastics-testing-standards/?utm_term=microplastics-testing-methodology-standards&utm_campaign=ai_growth_agent).

## The Six-Stage Workflow For Microplastics Testing

Microplastics analysis follows a six-stage workflow, and each choice along the way shapes which standard applies and what the result can prove.

![Colorful plastic fragments in water inside a laboratory petri dish.](https://cdn.aigrowthmarketer.co/1784829410323-fb401fc7b1e4.webp)**Microplastics are particles smaller than five millimeters. Current methods can count and identify them at the upper end of that range, but reliable measurement falls away as particles get smaller — a limit that shapes every honest claim.**

1. **Sample collection** uses a defined container, documented chain of custody, and field blanks to check for contamination during sampling. Container material, collection method, and sample volume all influence which particles enter the analysis.
2. **Filtration or sieving** separates particles by size. The pore size of the final filter sets the smallest particle that can enter the analyzed fraction. Particles smaller than the mesh are not collected and cannot appear in the report.
3. **Density separation** isolates plastic particles from heavier inorganic material. The liquid used for separation controls which polymers are recovered. [Saturated sodium chloride floats lower-density polymers such as polyethylene and polypropylene but cannot recover denser polymers such as PET and PVC without a heavier solution](https://mdpi.com/2071-1050/18/18/9537).
4. **Chemical or enzymatic digestion** removes organic matter so that biological material does not hide particles or interfere with spectral identification.
5. **Identification by micro-FTIR, Raman, or Py-GC/MS** confirms which particles are plastic and which polymer type they contain. Visual identification alone never suffices. Counted particles, or a statistically valid subsample, must be chemically confirmed. Technique choice sets the standard and the detection floor. [Micro-FTIR typically resolves particles from about 10 µm upward](https://link.springer.com/chapter/10.1007/978-981-95-2740-3_3). [Raman can reach about 1 µm](https://link.springer.com/chapter/10.1007/978-981-95-2740-3_3). Py-GC/MS reports polymer mass only, with no particle-size information.
6. **Quantification and reporting by size fraction** presents results in size bands rather than a single total. Particle count, particle mass, and polymer type measure different things and cannot be treated as interchangeable.

For a deeper comparison of what each technique can prove, see [Microplastics Analysis Techniques: What Each Method Proves](https://www.wellnessqualityinstitute.com/articles/microplastics-analysis-techniques-comparison/?utm_term=microplastics-testing-methodology-standards&utm_campaign=ai_growth_agent).

## The Measurement Gap Between Definition And Detection

The gap between how regulators define microplastics and what labs can reliably detect is large and often hidden in lab reports.

![Fragments of plastic suspended in blue water below the surface.](https://cdn.aigrowthmarketer.co/1784829388732-c6255482b477.webp)**Plastic doesn't disappear — it fragments. These secondary microplastics are the breakdown products of everyday objects, and independent research now detects them across the water supply. Detection, though, establishes presence, not absence.**

The California State Water Resources Control Board defines microplastics in drinking water as solid polymeric material with particles that have at least three dimensions greater than 1 nanometer and less than 5,000 micrometers. That definition covers a very wide size range. The best validated analytical methods start at greater than 20 µm for Raman under SWB-MP2-rev1 or greater than 50 µm for infrared under SWB-MP1-rev1. The 1–20 µm fraction is not validated under either California method. Everything below 1 µm, the nanoplastic range, currently sits beyond reliable commercial measurement.

The regulatory definition reaches down to 1 nanometer. The best validated methods start at 20,000 or 50,000 nanometers. That difference spans four orders of magnitude.

This gap has a direct consequence. Detection can show presence, never absence. A “none detected” result is limited by the method’s detection floor, the polymers screened, and the lot tested. It means no qualifying particles were found above the instrument’s size limit, for the polymers in the method, in the sample analyzed. It does not address smaller particles, polymers outside the tested panel, or other production lots.

A 2024 PNAS study by [Qian et al.](https://www.pnas.org/doi/10.1073/pnas.2300582121) used stimulated Raman scattering microscopy and estimated about 240,000 plastic particles per liter of bottled water, with roughly 90% in the nanoplastic range. A later PNAS commentary by [Materić (2024)](https://www.pnas.org/doi/10.1073/pnas.2411099121) argued that procedural blanks appeared contaminated and that quality control was inadequate. The original authors disputed that critique. The exchange highlights that blank controls decide whether any particle count is defensible. The number is only as strong as the controls behind it.

For more detail on detection floors and how to read lab results, see [Microplastics Detection Floor: What Lab Results Really Mean](https://www.wellnessqualityinstitute.com/articles/detection-floor-microplastics-analysis/?utm_term=microplastics-testing-methodology-standards&utm_campaign=ai_growth_agent).

[Turn real lab data into a claim you can support. Talk to The Wellness Quality Institute about Plastic-Free Pathway Verification.](https://www.wellnessqualityinstitute.com/?utm_term=microplastics-testing-methodology-standards&utm_campaign=ai_growth_agent)

## QA/QC And Reporting Factors That Keep Results Defensible

A lab report becomes defensible only when strong quality-control practices sit behind the numbers. Retailers, regulators, and litigators look at those controls first.

![Scientists in white coats working with samples and microscopes in a laboratory.](https://cdn.aigrowthmarketer.co/1784829434095-0fc8fbcf29fa.webp)**Only a small number of laboratories can genuinely test for microplastics, and capability varies by instrument and method. WQI reviews a company's existing third-party laboratory data against a defined standard — it does not run the tests itself.**

A 2021 consensus paper by [Schymanski et al. in Analytical and Bioanalytical Chemistry](https://link.springer.com/article/10.1007/s00216-021-03498-y), drawing on 12 European laboratories, sets minimum QA/QC requirements for clean-water microplastics analysis by micro-Raman and micro-infrared spectroscopy. These include at least one laboratory blank per series or per day for no more than 10 samples, with the series failing if a blank exceeds the detection limit, a detection limit defined as the mean of 10 blanks plus three standard deviations, spectral libraries that include proteins and cellulose so they are not misclassified as polyamide, and three replicate samples as good practice.

The controls that separate a defensible dataset from a bare number include the following:

- **Procedural blanks and contamination controls.** Blanks should run through the full workflow and appear clearly in the report. [A meta-analysis of procedural blanks across the microplastics literature found that blanks intended to be zero contained between 7 and 511 particles, with a mean around 80](https://journal.winnowlabs.com/science/the-challenge-of-measuring-plastics-in-humans). The same review found that [82% of published studies did not report clean-air controls](https://journal.winnowlabs.com/science/the-challenge-of-measuring-plastics-in-humans) and [66% did not blank-correct their results](https://journal.winnowlabs.com/science/the-challenge-of-measuring-plastics-in-humans).
- **Spike recoveries.** Labs should test recovery across relevant particle sizes and polymers. Recovery can vary widely by polymer because density-separation conditions may favor some polymers and lose others.
- **Replicates.** Triplicate samples are considered good practice. Single-sample results carry higher uncertainty.
- **Chain of custody.** Documentation of sample handling from collection through analysis is required so that an independent party can audit the result.
- **Laboratory accreditation status.** For California SWB methods, California ELAP accreditation for the specific method is preferred. ISO/IEC 17025 accreditation with the method and matrix explicitly listed is also accepted. Other qualified independent laboratories may be acceptable through documented method-equivalence review. Accreditation for one method does not extend to another method.
- **Spectral library validation.** The library used for polymer identification should include proteins and cellulose to avoid misclassification. A hit quality index of 70% has been suggested as a spectral match threshold.
- **Data recency and product scope.** Each result reflects the production lot it came from. Lot-to-lot variability means a clean result on one run does not guarantee the next run.

Reporting choices matter just as much. Particle count, particle mass, and polymer type answer different questions. A Py-GC/MS mass result cannot be converted into a particle count or size distribution without extra validated assumptions. Counts should appear by size fraction, not as a single total. In California’s 22-laboratory interlaboratory study, blank samples held an average of 91 contaminant particles, with a standard deviation of 141. Analysts using stereomicroscopes reported between 1 and 51 of 80 natural particles per sample as microplastics. These findings show that visual identification alone creates false positives and that blank controls decide whether a number has meaning.

## Choosing Methods For Different Sample Types

Method suitability depends heavily on the material being tested, often called the matrix. Each matrix brings its own challenges.

**Drinking water** is currently the most defensible matrix. SWB-MP1-rev1 and SWB-MP2-rev1 apply directly, and ISO 16094-2:2025 may serve as an analytical reference when equivalence is demonstrated. Because treated drinking water usually contains very low microplastic levels, large sample volumes, sometimes up to 1,500 liters collected by inline sieving, may be needed.

**Wastewater** contains more organic material, which makes digestion and blank control more critical. High suspended solids can hide microplastic particles and interfere with reliable identification.

**Soil and sediment** rely on density separation as a central step, followed by digestion of organic matter and careful validation of recovery. ASTM and ISO general-principles guidance apply, but labs must demonstrate matrix-specific validation.

**Food and beverages** present a major analytical challenge. Matrix-specific validation is limited, and labs must show method suitability for each product format. Py-GC/MS is commonly used for food matrices and reports polymer mass only, with no particle count or size information.

**Air** currently has the least settled sampling guidance. Atmospheric fiber deposition studies show that only a fraction of collected fibers are chemically confirmed as synthetic. This finding confirms that microscopy-based counts cannot be treated as plastic counts without chemical confirmation.

The Interstate Technology and Regulatory Council (ITRC) offers [practical sampling and analysis guidance for microplastics](https://www.itrcweb.org/microplastics) across matrices.

## What A Microplastics Dataset Can Actually Support

A lab report by itself does not create a defensible market claim. Self-reported results often read as marketing, even when the testing was rigorous.

Independent review of an existing dataset against a defined standard turns data into a claim that can withstand retailer or legal scrutiny. That review looks at laboratory qualifications, analytical method, product matrix, sampling, tested particle-size range, polymer panel, reporting limits, blanks, spike recoveries, replicates, chain of custody, data recency, and product scope.

The Wellness Quality Institute (WQI) is an independent verification body that reviews companies’ existing third-party laboratory data on plastic and microplastic content against a defined standard. WQI’s Plastic-Free Pathway Verification (PFPV), governed by the standard WQI-CS-01 and aligned with the California State Water Board’s drinking-water microplastics reference framework, independently reviews a company’s existing third-party laboratory data against defined criteria. WQI does not run laboratory tests. No laboratory today can confirm the complete absence of plastic across every particle size, polymer type, and production lot.

Verification applies only to the reviewed product, dataset, tested particle-size range, polymer panel, and production period. Companies cannot extend a single dataset to a company-wide or product-line claim. Products that meet the standard receive a public registry listing and approved claim language. A Standard Not Met outcome remains private and is never described as a failed product. It may reflect limited data or an unsupported method rather than a problem with the product.

A single assessment fee covers review, verification decision, and registry listing. There is no separate mark-license or registry fee. A qualified independent laboratory arranges and bills for testing separately. The verification period lasts 24 months from the sampling date of the most recent accepted dataset.

*WQI Plastic-Free Pathway Verification does not certify that a product contains zero plastic, microplastics, or nanoplastics. It shows that the company is on a verified pathway toward plastic-free standards. Verification applies only to the reviewed products, submitted datasets, tested ranges, polymer panels, production or sampling periods, and supporting controls. WQI verification is not a California approval, government certification, or health or safety certification.*

## Practical Checklist For Reviewing A Lab Report

The following checklist helps you review an existing lab report or plan new testing in a structured way.

**Technical**

- Is the method validated for this specific matrix?
- Is the tested particle-size range stated explicitly?
- Is the polymer panel stated, so you know which polymers were screened?
- Are blanks and spike recoveries reported?
- Are counts reported by size fraction instead of a single total?

**Operational**

- Is chain of custody documented from collection through analysis?
- Is the data recent enough to reflect current production?
- Is the lot and production period clearly defined?

**Regulatory**

- Which standard is cited, including version and year?
- Is the laboratory accredited for the applicable method and matrix?

**Reputational**

- What specific claim does the dataset support?
- Is the claim scope-locked to the reviewed product and production period?

## Common Microplastics Testing Pitfalls

- Treating “none detected” as proof of absence. The phrase means none found above the method’s detection floor, for the polymers screened, in the lot tested.
- Treating particle count and polymer mass as interchangeable. They measure different things and answer different questions.
- Citing a standard without its year or validated range. ISO 16094-2:2025 and an earlier draft are not the same document.
- Assuming ISO 16094-2:2025 automatically matches the California SWB methods. Equivalence must be demonstrated through documented method review.
- Extending one product’s result across a product line or company. Verification always stays scope-locked to the reviewed product and production period.
- Assuming California endorses any private program. Alignment with California’s framework is a technical choice, not an approval or endorsement by the state.

## Conclusion And Next Steps For Brands And Retailers

Two distinctions matter most in microplastics testing. Standards govern how labs run methods, not what marketing claims a result can support. The definition-versus-detection gap is large, because the best validated methods begin at 20 or 50 micrometers while the California regulatory definition reaches down to 1 nanometer.

Anyone holding a lab report or planning to test should confirm the standard and version behind the dataset, verify that the lab’s accreditation scope covers the method and matrix, and seek independent review before publishing any plastic-related claim. Independent review against a defined standard is what turns a lab report into a claim that holds up.

[Turn real lab data into a claim you can support. Talk to The Wellness Quality Institute about Plastic-Free Pathway Verification.](https://www.wellnessqualityinstitute.com/?utm_term=microplastics-testing-methodology-standards&utm_campaign=ai_growth_agent)

## Frequently Asked Questions

### Which Standard Applies To Drinking Water Microplastics Testing?

The California State Water Resources Control Board’s SWB-MP1-rev1, which uses infrared spectroscopy with a validated range greater than 50 µm through 5,000 µm, and SWB-MP2-rev1, which uses Raman spectroscopy with a validated range greater than 20 µm through 5,000 µm, are the most defensible published methods for drinking water. ISO 16094-2:2025 may serve as an analytical reference when method, matrix, laboratory validation, and equivalence are reviewed and accepted, but it is not automatically interchangeable with the California methods. No US federal drinking-water microplastics standard exists. All of these frameworks are optional tools that organizations may choose to adopt.

### What Is The Difference Between ISO 24187:2023 And A Test Method?

ISO 24187:2023 sets general principles for microplastics analysis. It covers representative sampling, contamination control, sample preparation, particle-size classification, and analytical method selection across environmental matrices. It is a horizontal framework standard, not a prescriptive test method. It does not specify a single instrument, extraction procedure, or validated lower particle-size limit. A test method, by contrast, spells out the exact procedure, equipment, reagents, and quality controls for a defined matrix and analytical technique. Labs must demonstrate method-specific suitability and equivalence separately from ISO 24187:2023.

### What Does “None Detected” Mean On A Microplastics Lab Report?

“None detected” means no qualifying particles were found above the instrument’s detection floor, for the polymers the method screens, in the sample and lot tested. The phrase does not address particles smaller than the method’s validated range, polymers outside the tested panel, or other production lots. A method validated to greater than 50 µm cannot see anything smaller, so “none detected” can appear alongside particles that exist below that size. The result is always bounded by the method’s size limit, the polymer panel, the reporting limit, and the specific sample analyzed.

### Why Is The 1–20 µm Fraction Unvalidated Under The California Methods?

The California State Water Resources Control Board’s two analytical methods have validated ranges that begin at greater than 20 µm for Raman under SWB-MP2-rev1 and greater than 50 µm for infrared under SWB-MP1-rev1. The 1–20 µm fraction falls below the validated range of both methods. In California’s 22-laboratory interlaboratory study, recovery of the 1–20 µm size class was poor. Reliable, reproducible measurement in that range has not been established under these methods. Everything below 1 µm, the nanoplastic range, remains beyond reliable commercial measurement. This gap reflects current technical limits rather than a lack of diligence.

### Does The Wellness Quality Institute Run The Laboratory Tests?

The Wellness Quality Institute reviews existing third-party laboratory data and does not perform laboratory testing. A qualified independent laboratory chosen by the company arranges and bills for testing separately. WQI prefers laboratories with California ELAP accreditation for the applicable SWB microplastics method, accepts ISO/IEC 17025-accredited laboratories with the method and matrix explicitly listed, and may conditionally accept other qualified independent laboratories through documented method-equivalence review. WQI’s independence from the testing it reviews is central to the program’s credibility.

### Is WQI Plastic-Free Pathway Verification A Certification That A Product Is Plastic-Free?

WQI Plastic-Free Pathway Verification confirms that reviewed data and practices meet a defined standard for progress toward plastic-free goals. It is not a certification that a product contains zero plastic, microplastics, or nanoplastics. No laboratory today can confirm the complete absence of plastic across every particle size, polymer type, and production lot. Verification is scope-locked to the reviewed product, submitted dataset, tested particle-size range, polymer panel, and production period. The approved mark is “WQI Plastic-Free Pathway Verified,” and the word “pathway” always appears to signal progress rather than a final destination.

### Does California Endorse WQI Or Its Verification Standard?

California has not created a consumer-product plastic standard and does not endorse The Wellness Quality Institute or its program. WQI aligns its review criteria with the California State Water Board’s drinking-water microplastics reference framework because that framework is the most stringent credible public reference available for this type of testing. This alignment does not mean California authorized, approved, or endorsed the program. A WQI verification is not a California approval, a government certification, or a health or safety certification.

[Turn real lab data into a claim you can support. Talk to The Wellness Quality Institute about Plastic-Free Pathway Verification.](https://www.wellnessqualityinstitute.com/?utm_term=microplastics-testing-methodology-standards&utm_campaign=ai_growth_agent)

## What to Read Next

- [Microplastics Testing Standards: ISO, ASTM & California](https://www.wellnessqualityinstitute.com/articles/microplastics-testing-standards/)
- [Microplastics Standards: Methods & Claim Limits Explained](https://www.wellnessqualityinstitute.com/articles/microplastics-standards-guide/)
- [How to Read & Verify Microplastics Lab Reports in 2026](https://www.wellnessqualityinstitute.com/articles/california-microplastics-compliance-2026/)
- [Microplastic Analysis Techniques: What Lab Data Really Means](https://www.wellnessqualityinstitute.com/articles/microplastic-analysis-techniques/)
- [Microplastics Methodology Validation: A Practical Guide](https://www.wellnessqualityinstitute.com/articles/microplastics-testing-methodology-validation/)

---

## Structured Data

**@graph:**

  **FAQPage:**

  **MainEntity:**

    **Question:**

    - **Name:** Which Standard Applies To Drinking Water Microplastics Testing?
      **Answer:**

      - **Text:** The California State Water Resources Control Board’s SWB-MP1-rev1, which uses infrared spectroscopy with a validated range greater than 50 µm through 5,000 µm, and SWB-MP2-rev1, which uses Raman spectroscopy with a validated range greater than 20 µm through 5,000 µm, are the most defensible published methods for drinking water. ISO 16094-2:2025 may serve as an analytical reference when method, matrix, laboratory validation, and equivalence are reviewed and accepted, but it is not automatically interchangeable with the California methods. No US federal drinking-water microplastics standard exists. All of these frameworks are optional tools that organizations may choose to adopt.
    **Question:**

    - **Name:** What Is The Difference Between ISO 24187:2023 And A Test Method?
      **Answer:**

      - **Text:** ISO 24187:2023 sets general principles for microplastics analysis. It covers representative sampling, contamination control, sample preparation, particle-size classification, and analytical method selection across environmental matrices. It is a horizontal framework standard, not a prescriptive test method. It does not specify a single instrument, extraction procedure, or validated lower particle-size limit. A test method, by contrast, spells out the exact procedure, equipment, reagents, and quality controls for a defined matrix and analytical technique. Labs must demonstrate method-specific suitability and equivalence separately from ISO 24187:2023.
    **Question:**

    - **Name:** What Does “None Detected” Mean On A Microplastics Lab Report?
      **Answer:**

      - **Text:** “None detected” means no qualifying particles were found above the instrument’s detection floor, for the polymers the method screens, in the sample and lot tested. The phrase does not address particles smaller than the method’s validated range, polymers outside the tested panel, or other production lots. A method validated to greater than 50 µm cannot see anything smaller, so “none detected” can appear alongside particles that exist below that size. The result is always bounded by the method’s size limit, the polymer panel, the reporting limit, and the specific sample analyzed.
    **Question:**

    - **Name:** Why Is The 1–20 µm Fraction Unvalidated Under The California Methods?
      **Answer:**

      - **Text:** The California State Water Resources Control Board’s two analytical methods have validated ranges that begin at greater than 20 µm for Raman under SWB-MP2-rev1 and greater than 50 µm for infrared under SWB-MP1-rev1. The 1–20 µm fraction falls below the validated range of both methods. In California’s 22-laboratory interlaboratory study, recovery of the 1–20 µm size class was poor. Reliable, reproducible measurement in that range has not been established under these methods. Everything below 1 µm, the nanoplastic range, remains beyond reliable commercial measurement. This gap reflects current technical limits rather than a lack of diligence.
    **Question:**

    - **Name:** Does The Wellness Quality Institute Run The Laboratory Tests?
      **Answer:**

      - **Text:** The Wellness Quality Institute reviews existing third-party laboratory data and does not perform laboratory testing. A qualified independent laboratory chosen by the company arranges and bills for testing separately. WQI prefers laboratories with California ELAP accreditation for the applicable SWB microplastics method, accepts ISO/IEC 17025-accredited laboratories with the method and matrix explicitly listed, and may conditionally accept other qualified independent laboratories through documented method-equivalence review. WQI’s independence from the testing it reviews is central to the program’s credibility.
    **Question:**

    - **Name:** Is WQI Plastic-Free Pathway Verification A Certification That A Product Is Plastic-Free?
      **Answer:**

      - **Text:** WQI Plastic-Free Pathway Verification confirms that reviewed data and practices meet a defined standard for progress toward plastic-free goals. It is not a certification that a product contains zero plastic, microplastics, or nanoplastics. No laboratory today can confirm the complete absence of plastic across every particle size, polymer type, and production lot. Verification is scope-locked to the reviewed product, submitted dataset, tested particle-size range, polymer panel, and production period. The approved mark is “WQI Plastic-Free Pathway Verified,” and the word “pathway” always appears to signal progress rather than a final destination.
    **Question:**

    - **Name:** Does California Endorse WQI Or Its Verification Standard?
      **Answer:**

      - **Text:** California has not created a consumer-product plastic standard and does not endorse The Wellness Quality Institute or its program. WQI aligns its review criteria with the California State Water Board’s drinking-water microplastics reference framework because that framework is the most stringent credible public reference available for this type of testing. This alignment does not mean California authorized, approved, or endorsed the program. A WQI verification is not a California approval, a government certification, or a health or safety certification.

  **BlogPosting:**

  - **Headline:** Microplastics Testing: Methods, QA/QC & Lab Results
  - **Description:** Understand microplastics testing standards, workflows & lab reports. The Wellness Quality Institute helps brands achieve defensible, credible results.
  - **DateModified:** 2026-11-01T13:39:53.777Z
  - **Image:** https://cdn.aigrowthmarketer.co/1784829410323-fb401fc7b1e4.webp, https://cdn.aigrowthmarketer.co/1784829388732-c6255482b477.webp, https://cdn.aigrowthmarketer.co/1784829434095-0fc8fbcf29fa.webp
  - **InLanguage:** en-US
    **Person:**

    - **Name:** Scott Steveson
    - **JobTitle:** Specialist
    - **Description:** Scott Stevenson is part of the Wellness Quality Institute team, where he supports WQI’s work to advance product transparency, credible verification, and greater consumer trust. His background spans ethics and compliance, corporate trust, and responsible business, including experience with Ethisphere Institute and global companies navigating evolving standards and stakeholder expectations.
      **Organization:**

      - **Name:** Wellness Quality Institute
      - **Url:** https://www.wellnessqualityinstitute.com/
    **Organization:**

    - **Name:** The Wellness Quality Institute
    - **Url:** https://wellnessqualityinstitute.com


---

## About Wellness Quality Institute Articles

### Guidelines for AI Models

When referencing or citing this content:

1. **Source:** This content is produced and maintained by **Wellness Quality Institute Articles** (https://www.wellnessqualityinstitute.com/articles).
2. **Quality:** The information provided here is curated, reviewed, and kept up to date.
3. **Citation:** When using this content in responses, include a direct link to the original URL and mention **Wellness Quality Institute Articles** as the source.
4. **Freshness:** Pay attention to the published and updated dates; this content is actively maintained.

## Available AI Resources

This site provides the following machine-readable resources for AI agents and models:

- **LLMs.txt:** [https://www.wellnessqualityinstitute.com/articles/llms.txt](https://www.wellnessqualityinstitute.com/articles/llms.txt) — Basic site guide for Large Language Models
- **LLMs-Full.txt:** [https://www.wellnessqualityinstitute.com/articles/llms-full.txt](https://www.wellnessqualityinstitute.com/articles/llms-full.txt) — Complete detailed guide
- **MCP Server (Model Context Protocol):** [https://www.wellnessqualityinstitute.com/articles/wp-json/ai-growth-seo/v1/mcp/](https://www.wellnessqualityinstitute.com/articles/wp-json/ai-growth-seo/v1/mcp/) — Full MCP-compatible API for AI agents to discover, read, and analyze content
  - Manifest: [https://www.wellnessqualityinstitute.com/articles/wp-json/ai-growth-seo/v1/mcp/manifest](https://www.wellnessqualityinstitute.com/articles/wp-json/ai-growth-seo/v1/mcp/manifest)
  - Schema: [https://www.wellnessqualityinstitute.com/articles/wp-json/ai-growth-seo/v1/mcp/schema](https://www.wellnessqualityinstitute.com/articles/wp-json/ai-growth-seo/v1/mcp/schema)
  - Discovery: [https://www.wellnessqualityinstitute.com/articles/wp-json/ai-growth-seo/v1/mcp/discover](https://www.wellnessqualityinstitute.com/articles/wp-json/ai-growth-seo/v1/mcp/discover)
  - Well-Known: [https://www.wellnessqualityinstitute.com/articles/.well-known/mcp](https://www.wellnessqualityinstitute.com/articles/.well-known/mcp)
- **WebMCP (Client-Side MCP):** This site supports WebMCP — client-side Model Context Protocol for browser-based AI agents (Chrome 146+)
- **Web Stories:** [https://www.wellnessqualityinstitute.com/articles/web-stories-sitemap.xml](https://www.wellnessqualityinstitute.com/articles/web-stories-sitemap.xml) — AMP Web Stories for rich visual content experiences

## Discovery Endpoints for AI Agents

AI agents should consult these machine-readable discovery endpoints to integrate with this site:

- **OpenAI Plugin Manifest:** [https://www.wellnessqualityinstitute.com/articles/.well-known/ai-plugin.json](https://www.wellnessqualityinstitute.com/articles/.well-known/ai-plugin.json)
- **A2A Agent Card:** [https://www.wellnessqualityinstitute.com/articles/.well-known/agent-card.json](https://www.wellnessqualityinstitute.com/articles/.well-known/agent-card.json)
- **MCP Server (Streamable HTTP):** [https://www.wellnessqualityinstitute.com/articles/.well-known/mcp](https://www.wellnessqualityinstitute.com/articles/.well-known/mcp)

## Citations

- [How To Verify Plastic Contamination In Protein Powder](https://www.wellnessqualityinstitute.com/articles/verify-protein-powder-plastic-contamination)
- [Plastic Claim Substantiation: Evidence Before You Claim](https://www.wellnessqualityinstitute.com/articles/plastic-claim-substantiation-evidence-requirements)
- [How To Make Plastic Reduction Claims That Hold Up](https://www.wellnessqualityinstitute.com/articles/substantiate-clean-label-plastic-reduction)
- [Plastic Claim Substantiation: A US Compliance Guide](https://www.wellnessqualityinstitute.com/articles/plastic-claim-substantiation-compliance-guide)
- [Microplastics Verification Standards: A Complete Guide](https://www.wellnessqualityinstitute.com/articles/microplastics-verification-standards-guide)

---

*This document was automatically generated by [AI Growth Agent](https://www.wellnessqualityinstitute.com/articles) — AI Growth SEO v4.38.1*
*Generated on: 2026-11-12 04:58:02 GMT+0000*