Jaundice is a common condition in babies less than a week old. Skin that turns yellow can be a sure sign that a newborn is jaundiced and isn't adequately eliminating the chemical bilirubin.
However, that discolouration is sometimes hard to see, and severe jaundice left untreated can harm a baby.
The new app, developed by the University of Washington engineers and physicians, could serve as a screening tool to determine whether a baby needs a blood test - the gold standard for detecting high levels of bilirubin.
"Virtually every baby gets jaundiced, and we're sending them home from the hospital even before bilirubin levels reach their peak," said James Taylor, a UW professor of pediatrics and medical director of the newborn nursery at UW Medical Center.
"This smartphone test is really for babies in the first few days after they go home. A parent or health care provider can get an accurate picture of bilirubin to bridge the gap after leaving the hospital," Taylor said.
The app, called BiliCam, uses a smartphone's camera and flash and a colour calibration card.
A parent or health care professional would download the app, place the card on her baby's belly, then take a picture with the card in view. The card calibrates and accounts for different lighting conditions and skin tones.
Data from the photo are sent to the cloud and are analysed by machine-learning algorithms, and a report on the newborn's bilirubin levels is sent almost instantly to the parent's phone.
"This is a way to provide peace of mind for the parents of newborns," said Shwetak Patel, a UW associate professor of computer science and engineering and of electrical engineering.
A noninvasive jaundice screening tool is available in some hospitals, but the instrument costs several thousand dollars and isn't feasible for home use, researchers said.
Currently, both doctors and parents assess jaundice by looking for the yellow colour in a newborn's skin, but this visual assessment is only moderately accurate.
The UW team developed BiliCam to be easy to use and affordable for both clinicians and parents, especially during the first several days after birth when it's crucial to check for jaundice.
The team ran a clinical study with 100 newborns and their families at UW Medical Center.
They used a blood test, the current screening tool used in hospitals, and BiliCam to test the babies when they were between two and five days old.
They found that BiliCam performed as well as or better than the current screening tool. Though it wouldn't replace a blood test, BiliCam could let parents know if they should take that next step, researchers said.