About half the people with cystic fibrosis worldwide have never been diagnosed, by one widely cited estimate. Untreated, their life expectancy is under five years. In the United States, where the disease is caught early and treated, the projected median survival is 66 years.
That gap is not primarily a knowledge problem. It is a logistics problem. The test that confirms cystic fibrosis requires equipment and trained technicians that are available almost exclusively at accredited CF centers in major children’s hospitals.
A study published in npj Digital Medicine on July 28, 2026, describes a system built to close that gap: two flexible stickers, a button battery, and a smartphone camera, at a reported cost of roughly one dollar per test.
How the Sticker Test Works
The technology, called CF SWIFT, was developed by John Rogers’ bioengineering group at Northwestern University’s Querrey Simpson Institute for Bioelectronics with the Cystic Fibrosis Center at Ann & Robert H. Lurie Children’s Hospital of Chicago.
Two stickers are applied to the same patch of skin in sequence. The first stimulates sweat production using a chemical stimulant and a small button battery. The second is applied to the same spot and collects the sweat.
Then the analysis, normally the part requiring a laboratory, happens on a phone. A smartphone app photographs the collection sticker and measures changes in color density to calculate chloride concentration, the biomarker used to diagnose cystic fibrosis. The system requires only microliters of sweat, and the entire procedure takes less than an hour.
The standard method works differently. Sweat glands are stimulated with pilocarpine and a small electrical current, sweat is collected into a rigid coiled tube strapped to the arm or leg, and the sample goes to a lab for analysis.
Each piece requires something the sticker version does not: a stimulation unit, laboratory instrumentation, and a trained technician. Strip those out, and the test can, in principle, happen in a pediatrician’s office or a rural clinic.
Fifty-Five Patients, Two Tests Each
The study enrolled 55 participants: three healthy volunteers and 52 people with cystic fibrosis or CF-related conditions, ranging in age from infancy to 21 years. Each was tested with both the conventional method and the stickers.
“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,” said co-senior author Susanna McColley, MD, a CF specialist at Lurie Children’s and professor of pediatrics at Northwestern University Feinberg School of Medicine, in a hospital announcement.
Rogers framed the result in light of the group’s earlier work. A 2021 paper in Science Translational Medicine showed that chloride could be measured accurately on a sticker after sweat was stimulated by conventional equipment. The difference now, he said, is that CF SWIFT is a complete self-contained system including the soft stimulator unit, tested in a much larger population of children.
That distinction matters more than it might sound. The earlier sticker, supported in part by the NIH, still depended on the same specialized stimulation hardware sitting in accredited centers. Integrating stimulation into the patch eliminates the need for external equipment.
The Infants Who Have Not Been Tested Yet
McColley was direct about what has not been established.
“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 US are performed in the first weeks of life. Of course, FDA approval will be necessary for clinical use,” she said.
That limitation deserves emphasis. Ages in this study ranged from infancy to 21 years, but the population where the test would matter most—newborns in their first weeks—is precisely where sweat testing is hardest. Small infants sometimes cannot produce enough sweat, and rigid collection devices seal poorly on tiny arms. Families are occasionally sent home without a result and told to return.
The paper describes the clinical evaluation as taking place at a single pediatric CF center. A study spanning infancy to young adulthood at one site does not establish performance in a two-week-old. That is the validation McColley says is needed next.
The device also has no Food and Drug Administration clearance. Nothing described here is purchasable, and no clinician can order it.
Readers should know who stands where. Three authors, including Rogers, are affiliated with Epicore Biosystems, a company that develops and commercializes microfluidic sweat analysis devices. McColley is an unpaid clinical advisor to Epicore and a paid advisor to Vertex Pharmaceuticals, which makes CFTR modulator drugs. The paper states that CF SWIFT is not owned by Epicore, though the company may seek access to the technology through Northwestern’s technology transfer office. Rogers is an associate editor of npj Digital Medicine and was not involved in the journal’s review of the manuscript.
What Would Change if It Clears
Newborn screening in the United States flags infants for possible cystic fibrosis, and confirmatory sweat testing follows. For a family, hours from an accredited center are a burden. In countries without accredited labs, it may not be available at all.
Cheap disposable stickers analyzed by a phone would change that arithmetic. Single-use design also offers a secondary benefit by reducing the infection risk associated with reusable collection hardware.
The biology is straightforward. Mutations in the CFTR gene disrupt the channel that moves chloride across cell membranes, and one consequence is abnormally salty sweat. That is why a skin measurement can confirm a disease whose most severe damage occurs in the lungs and pancreas.
Earlier diagnosis is linked to better outcomes and longer survival, which is why McColley called broader access critical. CFTR modulator drugs have altered the disease course for many patients, but only those who have been identified.
For now, families should follow their state newborn screening program and their CF center’s guidance. Concerns about a child’s screening result belong with a pediatrician, not on hold for a technology that has not been cleared.
Key Questions Answered
What is CF SWIFT? It is a wearable system of two flexible skin stickers. One stimulates sweat using a chemical and a button battery; the other collects it, and a smartphone app measures chloride by analyzing color density in a photo.
How well did it perform? In 55 participants tested with both methods at a single pediatric CF center, the sticker results closely agreed with standard laboratory sweat chloride testing.
Can patients get this now? No. The system has no FDA clearance and is not commercially available. Researchers say multicenter validation in younger infants is required first.
Why does sweat chloride diagnose cystic fibrosis? Mutations in the CFTR gene disrupt chloride transport across cell membranes, leading to abnormally high chloride concentrations in sweat.
Who would benefit most? Infants in rural areas far from accredited CF centers, and people in countries with limited testing infrastructure. About half of people with CF worldwide are estimated to be undiagnosed.
Do the researchers have financial interests? Yes. Several authors are affiliated with Epicore Biosystems, which commercializes sweat analysis devices, and one co-senior author advises Vertex Pharmaceuticals for fees. The disclosures are stated in the paper.
