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Doctors may consider blood testing for the endocrine-disrupting chemicals per- and polyfluoroalkyl substances (PFAS) to assess community-wide exposure, the in new guidance this week.

In a new resource center detailing , the CDC said clinicians can order blood testing to measure PFAS levels for patients on an individual basis through Clinical Laboratory Improvement Amendments (CLIA)-certified commercial clinical laboratories. This kind of systematic PFAS blood testing may be particularly helpful for public health officials when looking into community-wide chemical exposures, the agency said.

Exposure to PFAS, often referred to as "forever chemicals," typically comes from contaminated food or water. Their chemical makeup allows them to reduce friction and resist oil and water, leading them to be commonly used in nonstick cookware, water-resistant fabrics, stain-resistant coatings, and personal care products.

Studies have linked exposure to these chemicals to a slew of health conditions, such as increases in cholesterol levels, decreases in birth weight, lower antibody responses to vaccines, kidney and testicular cancer, pregnancy-induced hypertension, preeclampsia, and changes in liver enzymes. Other research has also suggested a link between PFAS and thyroid disease, breast cancer, and ulcerative colitis.

While blood testing for PFAS is the more common way to measure exposure, urine testing is also sometimes used. Blood testing can inform clinicians of both recent and past exposures to PFAS, which can guide patients on exposure reduction, greater recognition of associated health effects, and "possible psychological relief" for the patient.

When considering if a patient needs PFAS blood testing, the CDC recommended the clinician first evaluate exposure history on an individual basis, and determine if the results may help reduce exposure.

That being said, there are limitations to such testing, including that blood tests won't actually help identify sources of PFAS exposure and that only certain types of PFAS can be detected in the blood. Testing also won't help link a current illness with exposure, nor predict future health outcomes.

On top of that, there are currently no approved medical treatments to reduce PFAS within the body. Some tips to reduce exposure include installing a water filtration system shown to reduce PFAS levels; test private well water; limit fish, meat, eggs, or dairy known to be contaminated with PFAS; and opt for cleaning and everyday consumer products free of PFAS.

These recommendations build upon 2022 exposure and testing guidance from the . In its report, NASEM called on the CDC to update its clinical guidance to advise clinicians to offer PFAS blood testing to patients who are likely to have a history of increased risk of exposure.

NASEM originally advised health screenings for patients exposed to PFAS based on the sum of certain PFAS levels: MeFOSAA, PFHxS, PFDA, PFUnDA, PFOS, PFOA, and PFNA. In their update, the CDC stated that clinicians who rely on NASEM's thresholds for making testing decisions should bear in mind that most people in the U.S. "will exceed NASEM's proposed thresholds for additional screening."

The Agency for Toxic Substances and Disease Registry said it will continue to review the latest PFAS science and provide future updates on the topic.

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