How to Turn Lab Data Into a Microplastics Verification Claim

Written by: Scott Steveson, Specialist

Key Takeaways

• A laboratory report alone does not create a defensible market claim. Independent verification against published criteria is required for retailer, procurement, and legal scrutiny.

• No laboratory method can confirm the complete absence of plastic across every particle size, polymer type, and production lot, so verification programs must state these technical limits clearly.

• WQI-CS-01 converts existing third-party laboratory datasets into registry-listed, scope-locked verification outcomes without requiring new testing.

• Verification under WQI-CS-01 uses California’s validated drinking-water microplastics methods as its technical anchor because they are the most stringent credible public reference currently available.

• US brands can turn real lab data into a defensible claim by contacting The Wellness Quality Institute about Plastic-Free Pathway Verification.

How Current ISO and ASTM Standards Handle Microplastics

There is no single ISO standard that governs microplastics testing across all products and uses. Instead, several documents work together, each with a defined scope, validated particle-size range, and specific limitations. Readers need to know what each standard covers and what it does not cover before deciding whether any laboratory dataset can support a market claim.

ISO 24187:2023 sets general principles for particle-based microplastics analysis across environmental samples such as water, sediment, and living organisms. It supports spectroscopic identification methods including FT-IR microscopy, Raman microscopy, and pyrolysis GC/MS. ISO 24187 does not prescribe a single test method or set regulatory thresholds. It instead lays out baseline principles that method-specific standards then build on.

ASTM D8401-24 covers microplastics characterization in water-based samples using pyrolysis-gas chromatography/mass spectrometry to identify polymer type and quantity. Micro-FTIR identifies polymer type, count, size, and shape down to about 10 µm, micro-Raman reaches 0.5–1 µm but can be disrupted by fluorescence from pigments and organic matter, and pyrolysis-GC/MS reports polymer mass and type but destroys all particle count, size, and shape information. These methods are not interchangeable, and a result from one method cannot be directly compared to a result from another.

California’s State Water Resources Control Board has published two analytical methods that currently serve as the most stringent credible public reference for drinking-water microplastics testing in the US. WQI-CS-01 uses these methods as its technical anchor because they provide the most defensible validated framework available, not because California requires consumer-product brands to use them.

Validated Analytical Method Ranges — Key Reference Methods

Method	Technique	Validated Particle-Size Range	Notes
SWB-MP1-rev1	Infrared spectroscopy	>50 µm through 5,000 µm	California SOP for drinking water, preferred method under WQI-CS-01
SWB-MP2-rev1	Raman spectroscopy	>20 µm through 5,000 µm	California SOP for drinking water, preferred method under WQI-CS-01
ISO 24187:2023	IR, Raman, pyrolysis GC/MS	Validated range method-dependent	General principles, no single prescribed method or regulatory threshold
ASTM D8401-24	Pyrolysis-gas chromatography/mass spectrometry	Matrix- and method-dependent	Identifies polymer type and quantity in aqueous matrices

The California drinking-water definition covers particles from 1 nanometer to less than 5,000 micrometers. The best validated methods begin at 20 or 50 micrometers, which are thousands of times larger than the lower definitional boundary. The 1–20 µm fraction is not validated under either California method, and everything below 1 µm, the nanoplastic range, is currently beyond reliable commercial measurement. This gap reflects the current state of the science and explains why no product can be verified as plastic-free.

How Current Regulations Treat Microplastics

Given these technical measurement limits, the regulatory landscape remains unsettled. There is no US federal standard governing microplastics in consumer products. California is the only state that requires statewide microplastics monitoring, directing large public water systems to test for and disclose microplastics data under its drinking-water program. The program includes monitoring of both untreated source water and treated drinking water over several years. On June 18, 2026, California’s Department of Toxic Substances Control finalized a rulemaking adding microplastics to its Candidate Chemicals List, effective October 1, 2026, which enables evaluation of consumer products for possible future regulatory action but does not yet create new manufacturer obligations.

At the federal level, the US Environmental Protection Agency notes a pressing need to develop and standardize collection, extraction, quantification, and identification methods for microplastics across media, which confirms that no consensus yet exists. The World Health Organization’s 2019 assessment of microplastics in drinking water reported low concern on limited evidence while stressing that this conclusion rests on incomplete information and that more research is urgently needed.

This regulatory vacuum explains why a raw laboratory report fails as a market claim. Self-reported data carries less weight than independently reviewed data. A report with an undefined scope, such as unclear products, production lots, particle-size range, or polymer types, cannot be evaluated by a retailer or a court. A “none detected” result also has limited meaning without the method’s detection floor, because it only confirms that no particles were found above that instrument’s lower limit.

Visual pre-screening of microplastic particles achieves only around 70% accuracy and frequently leads to overestimations, so spectroscopic confirmation is required for defensible identification. A 2023–2024 interlaboratory study of 84 laboratories found that identical microplastic reference samples produced results that disagreed by factors of two to ten, with coefficients of variation ranging from 45% to 129%. A laboratory report, however rigorous, cannot solve these comparability problems on its own.

This is where independent verification becomes essential. WQI-CS-01 is the published review standard the Wellness Quality Institute applies to existing datasets. It uses the California State Water Board’s drinking-water microplastics reference framework as a technical reference point because that framework represents the most stringent credible public reference available. Verification under WQI-CS-01 is available to US companies nationally, not only those operating in California.

Navigate the regulatory uncertainty with independently verified claims. Learn how the Wellness Quality Institute can help.

How To Evaluate Your Existing Laboratory Dataset

WQI-CS-01 evaluates a submitted dataset against defined criteria across several dimensions. Companies can use these criteria for a preliminary self-assessment before submitting and to understand what gaps their existing data may contain. The review focuses on the following elements.

Laboratory qualification. The Wellness Quality Institute qualifies laboratories by accreditation tier, and each tier reflects a different level of method validation. The preferred tier is California ELAP accreditation for the applicable SWB microplastics method, which aligns most directly with the verification framework. Where California ELAP accreditation is unavailable, the accepted tier is ISO/IEC 17025 accreditation with the microplastics method and the specific product matrix explicitly within the accredited scope. Other qualified independent laboratories may be conditionally accepted through documented method-equivalence review and Wellness Quality Institute technical approval. Knowing your laboratory’s tier before submitting helps avoid paying for testing that cannot support a review.

Analytical method and matrix suitability. The method must suit the specific product matrix. Microplastics testing in food and beverage products is historically challenging because proteins, lipids, and carbohydrates can interfere with analysis. A method validated for clean drinking water is not automatically suitable for a protein-rich beverage. The Wellness Quality Institute Phase 1 focuses on water and simple-liquid products, where testing methods are most defensible.

Polymer panel. The minimum target polymer panel under WQI-CS-01 is eight polymer types, with four designated as anchor polymers that require confirmed identification.

WQI-CS-01 Minimum Target Polymer Panel

Polymer	Abbreviation	Anchor Polymer	Common Source
Polyethylene	PE	Yes	Packaging films, bottles
Polypropylene	PP	No	Bottle caps, containers
Polyethylene terephthalate	PET	Yes	Beverage bottles
Polystyrene	PS	Yes	Foam packaging, containers
Polyvinyl chloride	PVC	Yes	Pipes, packaging
Polyamide (Nylon)	PA	No	Synthetic textiles, films
Polycarbonate	PC	No	Reusable containers, lenses
Polymethyl methacrylate	PMMA	No	Coatings, personal care

The review also requires reporting categories for other confirmed polymers and for unidentified particles with no spectral match. Particle count, color, and shape are reviewed as supporting context, not as the primary pass or fail line, because visual characteristics alone cannot chemically identify a polymer type.

Reporting limits and blanks. 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, while 82% of published studies did not report clean-air controls and 66% did not blank-correct their results. A “none detected” result is meaningful only when the reporting limits meet WQI requirements and blank data has been reported. Reporting limits below requirement make a non-detect result uninterpretable.

Chain of custody. A complete chain-of-custody record requires a unique sample identifier, named custodian identity at each step, timestamp of every transfer or access event, action taken, condition at handoff, and signature or electronic authentication. Missing any element creates a gap that breaks the record. An unexplained gap undermines confidence in any result derived from the sample, so WQI-CS-01 requires complete chain-of-custody documentation as part of the submitted dataset.

Data recency and production period. The verification period is 24 months from the sampling date of the most recent accepted dataset. Data older than this cannot support a current claim because lot-to-lot variability means a clean result on one production run does not guarantee the next.

How To Interpret the Binary Verification Outcome

Every WQI review produces one of two outcomes, with no partial results, provisional findings, or conditional passes.

Standard Met requires two conditions together. The dataset must satisfy all applicable technical and data-quality requirements, and no reportable target polymer particles can be detected within the tested particle-size range and approved reporting limits. A non-detect result alone is not enough, because the reporting limits themselves must meet WQI requirements or the non-detect is uninterpretable. Standard Met unlocks a scope-locked logo license, a public registry listing, and approved claim language tied to the specific reviewed evidence.

Standard Not Met is issued where one or more requirements are unsatisfied. This may reflect issues with the test results themselves, such as reportable particles detected or reporting limits below requirement. It may reflect problems with data quality and controls, such as incomplete data, inadequate blanks or contamination controls, or missing chain of custody. It may also reflect methodological gaps, such as an unsupported method, a method inappropriate for the matrix, laboratory qualification deficiencies, incomplete polymer analysis, or incomplete scope. Standard Not Met is a private outcome that carries no public claim, no logo rights, and no registry listing, and it is never described as a failed product. It frequently reflects the testing rather than the product. Companies may resubmit corrected or additional information for future review, and participating in the review process carries no public downside risk.

A single assessment fee covers review, verification decision, and registry listing. There is no separate mark-license or registry fee. Independent laboratory testing is arranged and billed separately by a qualified independent laboratory, and payment of the assessment fee does not guarantee a verification decision.

The Wellness Quality Institute’s 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. The Wellness Quality Institute verification is not a California approval, government certification, or health or safety certification.

How To Lock Scope and Use the Public Registry

Every verification decision is bound to a defined Verification Scope that covers the specific product or SKU, product matrix, production or sampling period, analytical method, tested particle-size range, target polymer panel, reporting limits, and supporting controls. A Standard Met outcome does not establish absence of plastic below the method floor, outside the tested range, outside the reviewed polymer panel, below the reporting limit, outside the registered product scope, or outside the registered production period.

Scope lock prevents a single product’s result from being extended to a product line or the company as a whole. This feature is the mechanism that makes the claim defensible. A claim narrow enough to be true is the only claim that holds up when a retailer, journalist, or litigant examines it.

Every Standard Met product receives a public registry entry recording the following elements:

• Verified party and product scope

• Product matrix and production or sampling period

• Tested particle-size range and applicable lower method limit

• Target polymer panel and approved reporting limits

• Testing laboratory and its accreditation reference

• Verification date, expiration date, and registry ID

• Approved result statement and current status (Active, Suspended, Expired, or Withdrawn)

Every public verification claim must include or link to the registry ID. Logo use may not stand alone as a product claim and must provide access to the Verification Scope record. Expired entries remain publicly visible and marked “Expired,” so the record stays honest over time instead of disappearing.

The approved mark is “WQI Plastic-Free Pathway Verified.” The word “pathway” is never optional and never dropped for brevity. The mark may not be presented as meaning plastic-free, microplastic-free, nanoplastic-free, zero plastic, or certified. It may not imply California approval, government certification, or health or safety certification. The Wellness Quality Institute provides a press release kit with approved headline options, quote templates, badge language, and explicit lists of claim language to use and avoid, so the compliant version is the easy version.

The verification period is 24 months from the sampling date of the most recent accepted dataset. Continued claim use after expiration requires re-verification using current data.

Lock your scope and get your product on the public registry. Start your Wellness Quality Institute verification.

Frequently Asked Questions

Does WQI verification mean the product has no plastic in it?

No. Current laboratory technology cannot confirm the complete absence of plastic across every particle size and polymer type. Current methods can only detect particles starting at 20–50 micrometers, leaving the smaller nanoplastic range below 1 micrometer beyond reliable measurement, as discussed in the standards section above. A WQI verification confirms only what the reviewed dataset actually supports within the tested particle-size range, using an independently reviewed method, for the specific product and production period reviewed. It is a statement about reviewed evidence, not a guarantee of a plastic-free product. The program name, Plastic-Free Pathway Verified, describes a verified direction of travel, not an arrived-at destination.

We already have lab data. Why do we need an independent review?

A laboratory report and a defensible market claim are different outcomes. Your data tells you what a laboratory found, but it does not tell the market what that finding supports or reassure a skeptical buyer that the interpretation is independent. Self-reported results are structurally discounted, regardless of how rigorous the underlying testing was. The Wellness Quality Institute review assesses whether the method suited the matrix, whether the reporting limits are adequate, whether blanks and contamination controls were run, whether chain of custody is complete, and what claim the data can actually carry. Many companies discover their existing data supports a narrower or a stronger claim than they assumed, and the review clarifies what their testing does and does not prove.

What happens if our data does not meet the standard?

A Standard Not Met outcome is private and carries no public claim, no logo rights, and no registry listing, and it is never described as a failed product. It frequently reflects insufficient data, an unsupported method, inadequate contamination controls, or incomplete scope rather than anything about the product itself. The company may submit corrected or additional information for future review. Participating in the review process creates no public downside risk, because the program is built to give companies a safe way to learn what their data actually supports before making a public claim.

Is this a certification, and does California endorse it?

It is a verification, not a certification. A certification implies a settled, guaranteed state, and no such guarantee is scientifically available for plastic or microplastic absence. Verification describes what actually happened, which is an independent review of a dataset against a defined standard. California has not created a consumer-product plastic standard and does not endorse the Wellness Quality Institute. As noted above, the Wellness Quality Institute aligns its criteria with California’s drinking-water microplastics reference framework as a technical reference, not because California authorized, approved, or endorsed the program. A WQI verification is not a California approval, a government certification, or a health or safety certification.

How long does verification last, and what can we say publicly?

Verification lasts 24 months from sampling, as detailed in the verification outcome section above. This time limit reflects lot-to-lot variability, because each result is tied to the specific production period tested. For public claims, companies may state that their dataset was reviewed and accepted under the Wellness Quality Institute Plastic-Free Pathway Verification standard, use the approved mark “WQI Plastic-Free Pathway Verified” for the specific products that met the standard, and use approved result language tied to their Verification Scope. Every public claim links to the registry ID. Companies may not say “plastic-free,” “microplastic-free,” “zero plastic,” or “certified,” and may not extend a single product’s result to a product line or the whole company.

Conclusion: Turning Real Microplastics Data Into Defensible Claims

The gap between a laboratory report and a defensible market claim is structural, not just paperwork. Self-reported data is discounted, undefined scope cannot be evaluated, and a “none detected” result is only as meaningful as the method’s detection floor allows. The standards landscape, including ISO 24187, ASTM D8401-24, and the California SWB methods, provides the analytical foundation, but no standard converts raw data into an independently reviewed, scope-locked, registry-listed claim on its own.

WQI-CS-01 supplies that independent review step. It evaluates existing datasets against defined criteria such as laboratory qualification, polymer panel, reporting limits, blanks, chain of custody, and scope, and produces a binary outcome that either unlocks approved claim language and a public registry listing or returns a private result the company can act on. The program is built around what the science can currently prove, and no further, and that restraint protects both brands and consumers.

US brands holding genuine laboratory data on plastic and microplastic content now have a pathway to use it that survives retailer scrutiny, procurement diligence, and legal challenge without overstating what any method can actually show.

Ready to convert your testing into a defensible market claim? Contact the Wellness Quality Institute to begin verification.