FRIDAY, April 13 (HealthDay News) -- During May, adults and children across the United States can get checked for asthma during the 11th annual Nationwide Asthma Screening Program, sponsored by the American College of Allergy, Asthma & Immunology.

The free screenings will be conducted at 300 locations throughout the country as part of National Asthma and Allergy Awareness Month. In its first 10 years, the program screened more than 100,000 people and referred more than half of them for a professional diagnosis.

During a screening, adults complete a 20-question test developed by the ACAAI for the program, while children under age 15 fill out a test designed for them. And there's another version that parents fill out for children up to 8 years old.

The screening also includes a lung function test that involves blowing into a tube and a meeting with an allergist to discuss whether a person requires a more thorough examination in order to determine if they have asthma.

"A cough that bothers you at night, shortness of breath when going up stairs, colds that go right to your chest -- these are all symptoms of asthma, but few people recognize them," Dr. John Winder, chairman of the Nationwide Asthma Screening Program, said in a prepared statement.

"Instead, people often make unnecessary lifestyle compromises to live with their condition, and there's no reason to do that. People with breathing problems, or who think their asthma could be better managed, should attend a free asthma screening," Winder said.

About 23 million Americans, including nine million children, have asthma, which kills about 4,000 people a year. There are a number of ways to control asthma.

The screening program is supported by the drug maker AstraZeneca.

More information

Here's where you can check for the nearest screening site.