Per- and poly-fluoroalkyl substances (PFAS) are a class of more than 9,000 chemicals used widely in industrial and consumer products. They are commonly known as ‘forever chemicals’ due to their extreme persistence in the environment and human body.

PFAS cross the placental barrier, accumulate in the growing fetus, are excreted in breast milk, and have been linked with a wide range of health effects including high cholesterol, several cancers, infertility, and low birth weight. They have contaminated drinking water for millions of Americans, and the U.S. Environmental Protection Agency recently proposed a drinking water goal of zero for two of the most common PFAS: PFOA and PFOS.

Blood test results can be used to document exposure, compare with levels in general populations, inform exposure reduction, and take health protective action. For individuals with elevated exposure, either through drinking water or occupational hazard, testing may be lifesaving or quality-of-life preserving, as it may lead to the early detection of health conditions including liver, kidney, and thyroid complications; immune system damage; several cancers; reproductive harm; and developmental abnormalities.

People with drinking water contamination or occupational exposure often want to know their PFAS exposure levels, but may have trouble gaining access to a blood draw and quality testing, which may not be readily available from doctors.

Traditional testing uses human serum, or plasma, to quantify exposure to PFAS. But getting the serum is cumbersome—you need a phlebotomist to draw blood, dry ice shipment with a biohazard designation, and a dedicated laboratory to separate serum from whole blood. Dried blood spots, like those collected from newborns using heel pricks, are not recommended for PFAS testing, as they risk accuracy due to the varying volume of blood in each spot.

Our study tested an improved finger prick approach using volumetric absorptive microsamplers, or VAMs, for self-collection of blood samples for PFAS testing. VAMs collect blood in a specific volume, which can then be shipped to a laboratory for accurate analysis. These microsamplers have been used by NIH for SARS-CoV-2 testing; we have applied them in a novel way to screen for PFAS in exposed populations.

We found that our new approach works well among people with elevated exposures, and can improve access to PFAS blood tests for individuals and researchers. Additionally, while the traditional approach uses serum our new approach relies on whole blood, which we found may offer a more comprehensive picture of the PFAS in the blood.

Importantly, our finger prick method enables anyone to test their own blood without participating in an academic study. Individuals can become aware of their PFAS exposure status while increasing access to PFAS blood samples that support research for future PFAS health impacts.

Users should take care to ensure proper self-collection and use sufficiently sensitive analytical methods. Also, the appropriate conversion must be applied when comparing with levels in serum, which some labs will do, but others may not. We found that multiplying the whole blood concentration by two provides a good estimate of the serum equivalent.

In our study, we sampled an exposed population, which means tested individuals have enough PFAS in their blood that laboratory analysis will detect it from the small volume of blood obtained by the microsampler using highly sensitive laboratory methods. However, it’s possible that some of the general population who have PFAS in their blood do not have levels high enough to show up from tests on microsampler-sized blood samples, even using a very sensitive test. Before our finger prick approach is broadly adopted for PFAS exposure and health research, future studies should test this new approach among people with lower levels more common in the general population.

The new PFAS blood test is available for purchase through empowerDX (legacy test and 40 compounds test both available). Visit the PFAS Exchange for information on PFAS blood testing and guidance on medical screening. The National Academies of Science, Engineering, and Medicine have a new Guidance on PFAS Exposure, Testing and Clinical Follow-up. Contact Dr. Carignan at the Michigan State University Center for PFAS Research for more information.