Colorado is the latest state requiring tests to find congenital heart defects in newborn infants.

The legislation was passed in early May and signed by the state’s governor last week.

The Colorado legislation excludes facilities above 7,000 feet until a determination is made on the correct pulse oximetry algorithm at that altitude. Once that is determined, the legislation requires that the State Board of Health will then require those higher elevation facilities do the screening.

Pulse oximetry tests blood oxygen levels using sensors placed on a newborn’s hand and foot. If levels are too low, more tests can be ordered that can uncover life-threatening heart defects, according to the American Heart Association.

The painless bedside test can be completed in as little as 45 seconds at less than $4 per baby, according to the AHA.

About 40,000 children are born with a heart defect every year in the United States. Heart defects are the most common birth defect in the United States, and early detection and treatment are crucial.

Without pulse oximetry testing, congenital heart defects might go undiagnosed because some newborns who have them appear healthy. A fourth of the defects are critical, requiring surgery or procedures with catheters within one year.  Pulse oximetry can speed diagnosis and detection, according to the AHA.

There are more than 40 states that currently require pulse oximetry tests for newborns. State legislation requiring the tests in Hawaii is now before the governor.