Why Unified Microplastics Research Standards Matter for Human Health Conclusions  

Unlike many conventional chemicals and materials, there is no broadly accepted scientific standard for identifying and counting microplastics in human tissues and fluids. Different laboratories use different sampling, contamination control, and analytical techniques, making it difficult for scientists and policymakers to compare and interpret the results.  

In their 2026 study, Lane et al. developed a framework with 14 distinct criteria to establish best practices for studies seeking to measure microplastics in human tissues, to ensure the reliability of data and suitability for assessing human health risk. The paper’s recommended best practices ranged from study design and contamination migration to particle characterization. Specific best practices included collecting tissue samples and whether those samples accurately represent the tissues or population being studied, laboratory contamination controls, detection limits, particle size, particle counts, particle shape and polymer identification.   

The Lane study applied its best-practice criteria to evaluate 133 datasets from 101 studies that attempted to measure microplastics in human tissues, performed in laboratories worldwide between 1998 and 2025.

Their results? NONE of the datasets met all the essential quality assurance/quality control criteria. Nearly two-thirds of studies (61.7%) achieved a total score (TAS) of ≤ 50% and over one-third of studies (36.1%) received scores of 0 in 7 or more criteria (i.e., half of the 14 criteria in the framework). As previously noted in Hermsen et al., 2018 (which introduced the scoring rubric used by Lane et al.), “Calculating the total accumulated score (TAS) indicates how comprehensively the study reports its methods and findings. However, if a study scores a ‘0′ on any single criterion, it is deemed unreliable, as each element is deemed essential” 

This does not mean that these 101 studies don’t have scientific value. The authors of the Lane paper caution that their framework is not intended to determine whether a study should have been published or to dismiss early exploratory research. The role of science is to ask and help answer important questions. Early research can be useful in hypothesis development, method improvement, and helping researchers to identify priorities for future research. Rather, Lane et al. cautions readers to think critically about whether the studies yielded data that is suitable for drawing conclusions about human health.  

Reliable Microplastics Studies Need Proper Controls

Detecting microplastics at very low levels is difficult because particles from laboratory air, water, sample handling, and equipment can contaminate samples. For example, a 2026 study found that even something as basic and universal as the use of nitrile gloves can release microplastics, potentially inflating reported results. 

This is why negative controls, or blank samples, are essential. They help researchers identify particles introduced during sample collection, processing, or analysis. 

Lane et al. found that: 

• Approximately 40% of the datasets reviewed did not adequately implement negative controls (blank, field, and/or process). 

• 30% of the microplastics datasets either did not use controls at all or did not report information about them. 

• Another 10% used only one or two controls. 

Additionally, positive controls are another important feature of any microplastics study intended to inform human risk assessment. They show whether a study’s methods can recover particles deliberately added to a sample, helping identify material lost during testing. Lane et al. found: 

• Approximately 77% of the datasets used no positive controls. 

Finally, studies must also include information on the limit of detection (LOD) or limit of quantification (LOQ). The LOD is the lowest concentration of microplastics a method can reliably distinguish from background levels. The LOQ is the lowest amount a method can measure with acceptable accuracy and precision. Lane et al. found: 

• Approximately 30% of studies failed to report a LOD or LOQ. 

These criteria are important for any microplastics research study intended to inform human risk assessment. Without these controls and limits in place, researchers cannot confidently determine whether reported particles came from the original sample, laboratory contamination, or limitations in the testing process. 

Microplastics Research Findings Should Be Biologically Plausible; Some Research Warrants Closer Examination  

Researchers searching for microplastics in the human body should use rigorous quality controls, and those quality controls should be standardized where possible. There are a number of well-established tools and frameworks which may be reasonably adopted or adapted for this purpose. 

But what if a study produces results that are implausible or extremely unlikely to occur outside a laboratory setting? If a study claims to find a particle inside a human organ or tissue, researchers should also ask whether physiology and human biology provide a plausible pathway for a particle of that size and shape to get there. The authors of the Lane paper found several results that warrant closer examination. Here are some examples:  

• One study claimed to find a particle that was 2.5 millimeters wide in lung tissue. However, deeply respirable particles are known to be typically smaller than 0.004 millimeters. 

• Two different studies claimed to find particles larger than 4 millimeters wide via nasal administration. This is roughly the same size as the diameter of a pencil eraser or the width of a small clothing button.  

• Another study claimed to find a particle in human blood that was more than 3 millimeters wide. However, the gut-lining cutoff, which ingested microparticles must cross to enter the blood, is known to stop particles larger than 0.15 millimeters. 

Unexpected findings are not automatically wrong, but they deserve closer scrutiny from researchers. The authors of the Lane paper recommend that microplastics researchers explicitly discuss whether their findings are biologically plausible, considering particle size and shape, known tissue-specific barriers, patient conditions, and the possibility of contamination or incidental detection. 

Some Microplastics Detection Methods Mistake Lipids for Polyethylene

Some studies of microplastics in human tissues use pyrolysis gas chromatography-mass spectrometry (Py-GC/MS), a highly sensitive method for detecting polymer-associated chemical signals. Py-GC/MS works by vaporizing a sample of tissue and searching for the chemical signatures in the vapor to try to identify plastics. 

The Lane paper notes that Py-GC/MS measurements in biological samples may produce misleading results. Residual lipids in human tissues can generate chemical signatures during pyrolysis that resemble the chemical markers used to identify polyethylene. In fact, some researchers believe a 2025 study that claimed to find microplastics in human brains was likely counting lipids in brain matter instead.

Stronger Quality Controls Can Advance Microplastics Research

The scientific community can strengthen confidence in human microplastics research through: 

• Better experimental controls and transparent reporting of blank results and particle recovery; 
• Standardized best practices for searching for microplastics in human tissues, including rigorous background contamination controls, and reference materials; 
• Better reporting of particle properties, including shapes and sizes of any detected particles, and analytical detection and quantification limits in laboratory equipment; 
• Interlaboratory validation and cross-calibration of analytical methods; and 
• Explicit evaluation of whether reported findings are biologically plausible. 

Conclusion

Research on microplastics in the human body can help answer important questions, but a reported detection is not, by itself, evidence of a health risk. Lane et al. found that none of the 133 datasets reviewed met every essential quality criterion, and several reported particles with no clear biologically plausible pathway to the tissue where they were allegedly found. 

That does not mean early studies are without value. Microplastics detection and risk assessment are areas of developing science, which means that there are not enough definitive studies to meaningfully evaluate for decision-making. Twenty of the 133 datasets (15%) had both an accumulated TAS > 14 (>50%) and 2 or fewer “zero” scores. While these studies do not yet meet the criteria set out by Hermsen (2018), this suggests that with careful design, future studies may provide more reliable data on which to evaluate microplastics in these systems. 

Standardized methods, proper controls, transparent detection and quantification limits, interlaboratory validation, and biological plausibility checks can help better distinguish credible findings from contamination or analytical error. Until then, researchers, journalists, and policymakers should interpret findings with appropriate caution to prevent inaccurate health conclusions from outpacing the evidence. 

References 

1. Lane, T., de Ruijter, V., Wardani, I., Barchiesi, M., Koelmans, A. (2026). A QA/QC screening framework to assess studies reporting microplastic presence in human organs, tissues, and bodily fluids. Environment International, Volume 214, 110429, ISSN 0160-4120. 
   https://doi.org/10.1016/j.envint.2026.110429. 

2. Hermsen, E., Mintenig, S. M., Besseling, E., & Koelmans, A. A. (2018). Quality criteria for the analysis of microplastic in biota samples: a critical review. Environmental science & technology, 52(18), 10230. 

3. Clough, M., Rivera, E., Ayala, A., Parham, R.,  Pennacchio, J., Thurber, H., Ault, A., Tewari, A., McNeil, A. (2026). Avoiding and reducing microplastic false positives from dry glove contact. Analytical Methods; 18 (14): 2914–2926.  
   https://doi.org/10.1039/d5ay01801c  

4. Karolinska Institutet. (2026, October 27). SciRAP reporting checklists. https://ki.se/en/imm/scirap-science-in-risk-assessment-and-policy/scirap-tools/scirap-reporting-checklists 

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6. Applied Particle Technology. (n.d.). What is respirable dust? Particle size, hazards, and exposure limits. https://www.appliedparticletechnology.com/article/what-is-respirable-dust-particle-size-hazards-and-exposure-limits 

7. Torres-Agullo, A., Karanasiou, A., Lacorte, S., 2023. Nasal lavage technique reveals regular inhalation exposure of microplastics, not associated from face mask use. Environ. Int. 178, 108129. https://doi.org/10.1016/j.envint.2023.108129. 

8. Zhang, M., Liu, T., Zhang, L., Hua, Z., Guo, Z., Dong, J., Tan, Q., Xie, Y., Yin, X., Yan, L., Pan, G., Sun, W., 2024. Assessment of microplastic exposure in nasal lavage fluid and the influence of face masks. J. Hazard. Mater. 480, 136069. https://doi.org/10.1016/j.jhazmat.2024.136069. 

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