CDC’s national health survey is visiting Greater Philadelphia. Here’s what to know.

A mobile health exam clinic parked outside a former fire station in Delaware County will aim to screen hundreds of Philadelphia-area residents, with the goal of helping the U.S. Centers for Disease Control and Prevention learn more about the health of average Americans.

The mobile clinic is part of the National Health and Nutrition Examination Survey (NHANES), which helps inform public health policy by gathering health and nutritional information about children and adults. The Philadelphia region is one of 20 locations tapped as screening locations for the survey this year.

NHANES travels the country, setting up mobile exam units and screening about 5,000 people annually. That unit is currently parked outside the former Briarcliffe Fire Company Station, at 767 Beech Ave. in Glenolden through September.

“We’re able to get a great representation of the whole nation because we literally travel over the entire nation,” said Duong (Tony) Nguyen, chief medical officer for NHANES.

The program chooses locations based on census tract data. They aim for a range of communities, from rural to urban.

Survey staff use a computer algorithm to randomly select participants. Only those who receive the mailed invitations can take part. Hundreds of children and adults across Delaware, Philadelphia, and Montgomery Counties were invited to participate.

People who receive an invitation are not obligated to participate in the survey, which requires health exams, lab tests, and interviews about eating habits.

But Nguyen encouraged people who have received an invitation to follow through. The health exams provided for free could otherwise cost thousands of dollars. Participants get access to all their test results, and can consult NHANES medical officers for help with interpreting the findings and determining next steps.

“We’ve been able to help them identify a health issue they may not have known about, and they can go seek care for it,” Nguyen said.

NHANES tries to make participation easier by providing reimbursement for transportation and child or adult care costs. Participants are eligible for a gift card worth up to $185.

The first step in the process is an in-person household interview. NHANES staff ask participants about their medical history, access to medical care, and lifestyle.

That’s followed by two phone interviews about eating habits, such as how much coffee they drink and what brand of bread they eat. The goal is to capture a snapshot of the typical American diet.

Participants have a physical exam at the mobile exam unit.

They also receive bone density scans, dental exams, and vision and hearing tests. Laboratory testing is another component, which allows them to evaluate things like cholesterol, kidney disease, liver disease, and exposure to harmful substances in the environment.

Information gathered by NHANES helps shape ongoing public health standards. For instance, the government uses height and weight measurements to update pediatric growth charts.

“It’s super important for us to be able to track and know and establish these reference criteria to see how we’re doing as a nation,” Nguyen said.

In the 1970s, the survey found that levels of lead in children across the U.S. were high. This data served as a driving force behind policy to remove lead from household paint and gasoline.

Since then, NHANES has found substantially lower levels of lead in kids.

The continuous nature of the survey allows for researchers to compare the nation’s health today versus decades ago.

“That longevity has allowed us to see where we’re making progress,” Nguyen said.