Valley Children’s doctors were the first in the U.S. to use a genetic test to determine if a certain antibiotic would lead to permanent hearing loss in a baby, the hospital said Tuesday.

A common antibiotic used to treat infections in infants has been known to attack human proteins vital to hearing development. While not usually a problem, babies born with a particular gene can suffer from long-term hearing loss because of the treatment, according to a hospital news release.

“Genes are like the individual instructions in a book that tell the body how to build and work, so understanding them is important in creating a treatment plan for each patient,” said Dr. Jeremy Woods, geneticist and director of the Valley Children’s Precision Medicine Program.

Test Gives Results in Less Than a Hour Versus Weeks

The test can give results back in less than an hour. To find out if the aminoglycoside class of antibiotic could affect long-term hearing in babies, doctors previously had to wait weeks for results.

Time can be critical for babies in the neonatal intensive care unit, where the antibiotic is typically used.

Now, the treatment requires only a cheek swab.

“Previously, we would have to wait weeks for the results of the MT-RNR1 genetic testing. Now, we can have results back in under an hour,” Woods said. “That gives us plenty of time to choose a safer antibiotic to treat a seriously ill baby.”

Valley Children’s Precision Medicine Program earlier this year also began using a genetic testing module that can more easily perform genome sequencing. As part of a Medi-Cal pilot program called Project Baby Bear, Valley Children’s is only one of five other hospitals to use rapid whole genome sequencing to improve care for critically ill infants with undiagnosed illnesses.

“Standardizing genome testing in the NICU underscores our commitment to utilizing cutting-edge technology and genetics to provide our patients with more than the best care, but the specialized kind of care they need,” Woods said.