More than 6 million children have been diagnosed with asthma, the most common chronic condition among kids.

But a new study suggests that many may have another condition and need different treatments.

Dr. Karen McCoy of Columbus Children's Hospital in Ohio said emergency room doctors see a child with breathing problems and immediately assume asthma and admit the patient.

But McCoy said a recent study found three out of four children who had good oxygen levels and appeared to have asthma actually had a condition known as vocal cord dysfunction, or VCD.

The symptoms are similar, but the treatments are vastly different. Kids with VCD are simply taught breathing exercises to help them cope. Children with asthma need medicine, sometimes steroids, to get better.

A simple breathing test called spirometry can tell doctors the difference. A few seconds on the machine may keep kids who don't have asthma out of the hospital, McCoy said.

"And, most importantly, not expose these kids to medications that may have tremendous negative side effects for them," McCoy said.

The study only looked at 20 cases, but could show a broader problem.

McCoy noted, however, that children can have both asthma and VCD.