More and more research is uncovering the dangers of PFAS, or per- and polyfluoroalkyl substances. There are an estimated 15,000 different PFAS chemicals with applications ranging from consumer products and textile coatings to industrial and commercial uses. It is estimated that up to 98% of Americans have detectable levels of PFAS, and public concern about the health effects of PFAS chemicals is increasing.
This primer provides an overview of the pertinent information that healthcare providers and clinicians can use if patients ask about PFAS exposure and testing. It summarizes information from guidance published by the CDC ATSDR and NASEM.
Disclaimer: This article is for educational and informational purposes only. Nothing in this article or on this web site represents medical advice or an offer of medical, diagnostic, or treatment products or services. Licensed medical professionals should seek additional information from other sources to inform clinical care.
Brief background on PFAS chemicals
PFAS compounds are a large group of synthetic chemicals that provide desirable properties such as water or grease resistance. It is estimated that there are nearly 15,000 PFAS chemicals going back to the late 1930s and early 1940s. Over the past decades their use has propagated across all industries. Common uses of PFAS include:
- Water-repellent coatings on raincoats and other outdoor clothing
- Greaseproof coatings on fast food cartons and wrappers
- Stain-resistant treatments on fabrics, carpets, furniture, and shoes
- Non-stick coatings on cookware and bakeware
- Additives in pesticides and other chemicals to increase shelf-life and potency
- Additives in lubricants to reduce friction
- Firefighting foam known as aqueous film-forming foam and protective treatments on firefighters’ personal protective equipment
As a result of their continued use over many decades, PFAS are now found in all natural environments (soil, water, air), in various animal species, and in humans.
Routes of exposure to PFAS
Human exposure to PFAS is primarily through ingestion and inhalation. Absorption through skin is also a concern, especially for high-risk occupations such as firefighting.
Ingestion of PFAS-contaminated food and beverages
PFAS ingestion is the main route of exposure for most people due to the many potential sources. PFAS ingestion can occur from:
- Drinking PFAS-contaminated water, which is one of the most common sources with over 2,000 municipalities having high concentrations
- Eating food grown or raised near PFAS-contaminated water or soil, including fruits, vegetables, meat, and dairy products
- Eating food that was packaged in PFAS-containing materials (processed food packaging, fast food wrappers and packaging, disposable cups or plates with water-resistant lining)
- Eating fish farmed in or caught from water contaminated by PFAS
- Eating foods prepared in cookware and bakeware coated with PFAS-containing non-stick materials such as Teflon, PTFE, and Xylan
- Accidental ingestion of PFAS-containing soil, dust, or other materials
- Infants drinking PFAS-contaminated breast milk
Inhalation of PFAS
In the home, a key source of PFAS inhalation is through dust contaminated with PFAS. Stain-resistant and water-repelling furniture, rugs, carpet, and other household items are the biggest culprits.
Occupational inhalation of PFAS occurs when PFAS-containing materials and ingredients are used. This can occur, for example, by breathing in PFAS as aerosols or fumes, or breathing PFAS-contaminated dust or other particles. Organizations including the American Conference for Governmental Industrial Hygienists (ACGIH) are defining safety guidelines for PFAS exposure through inhalation.
PFAS absorption through skin
Like many chemicals, PFAS can enter the body through direct contact with the skin. Water-repellent or stain-proof clothing is a key source of PFAS exposure, including those that contain “Gore-Tex.” Raincoats, as an example, are commonly made with PFAS-containing liners that can absorb into the skin. The use of certain personal care products and cosmetics can also lead to PFAS exposure through skin (e.g., long-lasting makeup, eyeliner, bronzers, foundation, nail polish, shampoo, and dental floss). Other household products like paints, varnishes, sealants could also expose people to PFAs chemicals but are less common.
Firefighters are particularly vulnerable to exposure through skin contact. Their protective turnout gear typically contains numerous PFAS compounds to provide waterproofing, heat protection, and grease resistance. Recently published findings from the National Institute of Standards and Technology (NIST) showed that firefighter turnout gear releases high levels of PFAS as normal “wear and tear” occurs. This then can lead to skin exposure and absorption of PFAS chemicals.
ADME properties of PFAS chemicals
Absorption, distribution, metabolism, and elimination studies of PFAS are somewhat limited and look at a subset of chemicals in animal models.
Generally, the following ADME properties of PFAS are expected:
- Absorption: Ingested PFAS is absorbed in the intestines and inhaled PFAS is absorbed in the lungs. Dermal absorption is limited compared to ingestion and inhalation.
- Distribution: PFAS binds to serum proteins, and to a lesser extent, tissue proteins in the liver, kidneys, and brain.
- Metabolism: Most PFAS compounds are not metabolized; some may be metabolized to other types of PFAS.
- Elimination: PFAS elimination occurs mainly in urine (clearance rate varies by sex and kidney function). PFAS is also eliminated through defecation. For women, elimination also occurs through menstruation and breastfeeding.
- Half-life: A few days to decades, depending on the specific PFAS.
The potential health impacts of PFAS exposure
Scientific research on PFAS has shown a range of health issues stemming from high exposure to PFAS. These include developmental disorders impacting children to high cholesterol, obesity, immune and hormone dysfunction, and greater risk of cancer in adults. The medical field’s current understanding of the health effects of PFAS is informed by a combination of animal studies, human in vitro tissue studies, and human observational studies.
Proven health effects
Sufficient associations between chronic PFAS exposure and negative health outcomes have been established for the following:
- Kidney and testicular cancers - PFOA (perfluorooctanoic acid) is an IARC Group 1 carcinogen
- Metabolic disruption, including hypercholesterolemia
- Reduced effectiveness in vaccinations among children
- Decrease in birth weight among children exposed to PFAS in utero
Probable health effects
Suggestive or limited association between PFAS exposure and negative health outcomes have been found for the following:
- Thyroid and sex hormone signaling disruption
- Altered liver enzyme function including changes in ALT, AST, ALP, and GGT
- Hypertension or preeclampsia during pregnancy
In 2021, the Agency for Toxic Substances and Disease Registry published a toxicological profile of perfluoroalkyl chemicals. This comprehensive review provides additional information about 12 specific PFAS chemicals and their health impacts.
As with other environmental exposures such as poor air quality, microplastics, glyphosate, and heavy metals, the health risks of PFAS to an individual could depend on a number of other factors. The frequency, duration, and quantity of PFAS exposure, comorbidities, general health status, and other factors may play a role in health outcomes.
CDC guidance for clinical evaluation and management of PFAS exposure
Occupational medicine specialists may be more likely to encounter patients with concerns about PFAS exposure. However, given the increasing awareness by the general public regarding PFAS, the following information could be helpful for all clinicians. The Agency for Toxic Substances and Disease Registry maintains a resource for clinicians with additional information on clinical evaluation and management.
Working with patients in the context of PFAS involves a number of steps. These include:
- Listening to the patient’s concerns about PFAS
- Getting an exposure history to identify current and past exposures, including guiding the patient on potential exposure sources
- Assessing the duration and level of PFAS exposure
- Recommending PFAS reduction strategies
- Educating patients about PFAS blood testing, including the benefits and limitations of such testing
- If patients choose PFAS blood testing, reviewing and recommending additional screening for patients at higher risk of disease (see NASEM advice below)
There are no approved medical treatments to reduce or remove PFAS from the body. Clinicians can work with patients based on their health history, exposure to PFAS, and if available, PFAS testing results, to develop individualized care plans.
Advice from the National Academies of Science, Engineering, and Medicine
NASEM proposes the following guidelines for PFAS blood testing results. These values are based on the sum of serum levels of 10 different PFAS compounds measured by NHANES.
- <2ng/mL : Low risk. No additional care needed
- 2 to <20 ng/mL: Moderate risk. Work on PFAS exposure reduction and screening for dyslipidemia, hypertension in pregnancy, and breast cancer
- ≥20 ng/mL: Add the following additional screenings at well visits: some text
- Thyroid function testing with serum TSH for patients >18 years
- Assess signs and symptoms of kidney cancer, including urinalysis, for patients >45 years
- Assess signs and of testicular cancer and ulcerative colitis in patients >15 years
NASEM estimated that for the U.S. population represented by NHANES in 2017–2018, 98% of people had PFAS levels ≥2 ng/mL; 9% had PFAS levels ≥20 ng/mL.
PFAS testing options
There are three main approaches to PFAS testing, which are blood serum testing, whole blood testing, and urinalysis.
Blood serum testing
Prescribing physicians and healthcare providers are able to order PFAS blood tests for their patients through Quest Diagnostics (Test Code 39307). This test is not available in all geographies, and ordering physicians should check availability. This test measures 6 different PFAS compounds and covers a subset of compounds as tested by the NHANES program. Alternatively, providers can guide patients to order their own blood serum PFAS test through Quest Health, which is a consumer service that measures 9 different PFAS compounds. This latter option still requires the patient to visit a Quest location for a venous blood draw.
Whole blood testing
Recently, labs have started using dried whole blood samples to test for PFAS. There are a few benefits to this. Firstly, the sample can be much smaller. Typically, just a few drops of blood are enough. Secondly, the sampling process can be done at home and needs no specialist medical knowledge. Patients can purchase these tests directly, get the results, and share these with their healthcare providers. Relentless Health provides a PFAS Core Panel test that is easy to use, affordable, and provides quick turnaround times.
Urinalysis
It is also possible to detect PFAS in urine samples. However, this is not such a widely used approach. The issue here is that each person’s body eliminates PFAS differently and at different rates. So, it is harder to draw conclusions about the results of urinalysis.
Additional PFAS resources for clinicians
The following resources are available from government agencies and organizations to inform clinicians about PFAS exposure and patient care.
NASEM Guidance on PFAS Testing and Health Outcomes
CDC / ATSDR PFAS Information for Clinicians - 2024
ATSDR Toxicological Profile of PFAS
ATSDR PFAS Blood Level Estimation Tool
Disclaimer: This article is for educational and informational purposes only. Nothing in this article or on the web site represents medical advice or an offer of medical, diagnostic, or treatment products or services. Anyone concerned about their health should consult a licensed medical professional.
