New Wearable Stickers Simplify Cystic Fibrosis Diagnosis

A pair of wearable stickers may transform diagnostic sweat testing for cystic fibrosis (CF), a genetic disorder that causes digestion and breathing problems. A study published in Digital Medicine found the technology to be reliably accurate compared with standard sweat testing.

Small, flexible, and gentle on babies’ delicate skin, the sweat test stickers are less expensive, simpler to use, and do not require specialized lab equipment or technical expertise, in contrast to the standard sweat testing process primarily available in accredited CF centers at children’s hospitals. Thus, the stickers can potentially provide greater access to the diagnostic test and timely treatment, especially for babies living in rural areas far from a CF center or lower-income countries where testing availability is limited.

“It has been estimated that about half of people with CF around the world have not been diagnosed. Without treatment, their life expectancy is less than 5 years of age. This is in stark contrast to 66 years, which is the projected median age of survival with treatment in the U.S. currently,” said co-senior author Susanna McColley, M.D., CF expert at the Ann & Robert H. Lurie Children’s Hospital of Chicago and professor of pediatrics at Northwestern University Feinberg School of Medicine. “The new technology, developed by the bioengineering team of John Rogers at Northwestern University’s Querrey Simpson Institute for Bioelectronics, in close collaboration with our cystic fibrosis center team, promises to make diagnostic testing for CF more readily available. This is critical, since earlier diagnosis is linked to better health outcomes and longer life.”

Diagnostic testing for CF measures sweat chloride. In the new system, the first sticker stimulates sweat production using a chemical and a button battery, while the second sticker is applied to the same spot to collect the sweat for analysis. An image of the sticker is used by a smartphone app to analyze chloride content through precise measurement of changes in color density. The entire procedure takes less than an hour to complete.

“This latest paper is a real advance over our previous report in Science Translational Medicine, which showed that sweat chloride could be accurately measured on a sticker after sweat stimulation using current technology. The new “CF SWIFT” device is a complete self-contained system, including the soft stimulator unit, with a much larger population of children studied and proof of clinical accuracy in measuring chloride,” stated co-senior study author John Rogers.

The current study included 55 participants—three healthy volunteers and 52 people with CF or CF-related conditions, with ages ranging from infancy to 21 years. Participants were tested using both the traditional sweat testing method and the new sticker technology.

“We found a high correlation in the results between the two methods, which demonstrates that the new technology reliably reflects sweat chloride measurements used for diagnosis of CF,” Dr. McColley said. “Before these sweat testing stickers become clinically available, however, we need to validate our findings in a multicenter study with younger infants, since most sweat tests in the U.S. are performed in the first weeks of life. Of course, FDA approval will be necessary for clinical use.”

Ann & Robert H. Lurie Children’s Hospital of Chicago is a nonprofit organization providing access to child healthcare. It is the only independent, research-driven children’s hospital in Illinois and one of less than 35 nationally. Exclusively focused on children, all Lurie Children’s resources serve their needs. Research at Lurie Children’s is conducted through Stanley Manne Children’s Research Institute, which is focused on improving child health, transforming pediatric medicine, and ensuring healthier futures. Lurie Children’s is the pediatric training ground for Northwestern University Feinberg School of Medicine. It is ranked as one of the nation’s top children’s hospitals by U.S. News & World Report.