Therapeutic Plasma Exchange Meets the Microplastics Panic

Microplastics are having a moment. They've turned up in blood, in placentas, in breast milk, and, most alarmingly, in a 2024 NEJM paper that's done more to shape the public conversation than almost anything else in this space, in carotid artery plaque, where their presence correlated with a higher rate of cardiovascular events.

Here's what's actually established: microplastic particles are measurably present in human tissue and blood, and we absorb them through what we eat, what we breathe, and what touches our skin. That part is real.

Here's what isn't established: whether any of it matters. There's no dose-response curve. No outcome data tying a given blood concentration to a given health effect. No consensus on whether the microplastics circulating in your blood on a Tuesday afternoon bear any meaningful relationship to the total burden sitting in your tissues. We have exposure. We do not have consequence, not yet, not with the kind of evidence that lets a clinician make a recommendation.

That gap is exactly the space a wellness industry moves into fastest. Uncertainty reads as opportunity. So when a paper crossed my desk this year claiming that therapeutic plasma exchange can lower your circulating microplastic burden, I wanted to like it. I run an apheresis clinic. I would love a legitimate new indication. I read the methods first, the way I always do.

What They Did

Weinstein and colleagues, publishing in the Journal of Clinical Apheresis in 2026, tested 114 patients undergoing 174 single-plasma-volume TPE procedures on a Spectra Optia system. Blood was drawn immediately before and after each procedure and tested for microplastic particles using PlasticTox, a proprietary assay that involves drying a blood sample on a card, mailing it to a central lab, staining the isolated particles with Nile Red, and counting them under fluorescence microscopy.

The procedures took place in functional medicine outpatient clinics. The indications were longevity support, postural orthostatic tachycardia syndrome, myalgic encephalomyelitis, and long COVID, none of which are established indications for TPE by any apheresis society guideline I'm aware of. No IRB approval was sought, because the authors classified this as normal-course-of-care data collection rather than research; consent was a checkbox on the standard TPE consent form, agreeing that results could be used anonymously in publications.

The Number That Should Stop You

The topline result, stated plainly: TPE lowered circulating microplastic counts, but only in patients who started with a lot of them. Below a certain threshold, TPE made things worse.

Starting MP (per 100μL)	Pre-TPE mean	Post-TPE mean	p-value
0–9	4.4	14.4	<0.001 (increase)
10–19	13.8	11.7	0.062 (no change)
20–29	23.6	16.1	0.040 (decrease)
≥30	52.2	21.1	<0.001 (decrease)

Read the top row again. Patients who started with the lowest microplastic burden had over three times as many circulating particles after the procedure meant to remove them. That's not noise; the p-value is under 0.001.

The explanation is almost certainly mechanical rather than biological: the apheresis tubing set and fluid bags themselves shed microplastic particles into the circuit as it runs. The paper's own tubing measurements bear this out: meaningful particle counts in the priming saline before it ever touched a patient. At low starting burdens, the plastic you're being infused through outpaces whatever the procedure removes. Only above roughly 30 particles per 100μL does removal clearly win.

Who's Selling This

Seven of the paper's thirteen authors are affiliated with Circulate Health, a company that provides contract TPE services to private clinics. The remaining four are officers of the clinics where the data were collected. I'm not raising this to imply fraud; the data appear to be honestly reported, reversal and all. But when the people measuring a therapy's effect are also the people selling it, that's a fact the reader needs before they get to the conclusion, not after.

An Assay Grading Its Own Homework

PlasticTox is described in the paper as validated by a CLIA-certified reference laboratory. The validation data itself is not disclosed; it's held as proprietary by the company that sells the test. So the entire quantitative backbone of this study rests on an assay whose performance characteristics you're asked to take on faith.

This is precisely the kind of thing laboratory medicine exists to prevent. We don't let a diagnostic test dictate a treatment decision until someone outside the company selling it has verified that the test measures what it claims to measure, reliably, across the range of values that matter clinically. An unvalidated assay with undisclosed methods, sitting downstream of a commercial incentive, isn't a minor limitation buried in a discussion section. It's the whole foundation, and it's built on trust rather than evidence.

What's Missing Entirely

Even if you grant every number in this paper at face value, even if TPE reliably lowers circulating microplastic counts above some threshold, nobody has shown that doing so changes anything for the patient. There is no clinical outcome data here. No symptom scores, no follow-up, no signal that a lower particle count translates to less disease of any kind. The paper answers whether a number can be moved. It does not, and cannot, answer whether moving it helps anyone.

Where I Land

I don't think the underlying question is silly. Whether microplastics move freely between tissue depots and the bloodstream, whether the blood compartment is a meaningful proxy for total body burden, or just a transit lane, is a real and interesting mechanistic question, and one worth studying properly. If it turns out blood truly is in dynamic equilibrium with tissue stores, apheresis might someday be a legitimate tool for something we don't yet have tools for.

But that is not what this paper demonstrates. What it demonstrates is a commercial TPE provider running a therapy already being sold to patients, measured with an assay the company can't independently verify, with no outcome data attached, and a result that reverses at exactly the exposure level most of their patients probably start at. The biology might be worth chasing. The product being sold on the back of it is not the same thing as evidence that it works.