A New Chloride Sweat Test for Cystic Fibrosis Screening

DESCRIPTION (provided by applicant): The CF Quantum(r) sweat test system is a rapid, easily administered, cost effective method to diagnose cystic fibrosis (CF). The CF Quantum(r) patch (Q-patch) uses an ion-exchange reaction to produce a white precipitate which varies in size based on the chloride ion concentration of the sweat sample. Reacting the Q-patch with a chloride-containing solution (i.e. sweat) yields two concentric circles on the patch. The ratio of the area of the inner circle to that of the outer ring provides a decimal ratio, which has a linear relationship with the chloride concentration. It is therefore possible to react the Q-patch with a chloride solution and find its concentration, expressed in millimoles, by applying a linear regression formula to the areas of the two concentric circles. This phase of the project will refine the Q-patch system to make it commercially viable. The system includes 1) sweat stimulation, 2) sweat collection and 3) sweat analysis. The stimulation method and collection cycle time will be optimized by comparing three new methods of transporting pilocarpine to the sweat glands and comparing the results to the current iontophoresis method. Improved data analysis involves the integration of the software program developed in phase I with a secure web based data transport system. The Q-patch will be scanned into an optical scanner, sent via the internet to a host server where the software program will "read" the Q-patch and calculate the chloride concentration automatically, eliminating all manual measurements and calculations. The results are immediately returned to the clinic along with a digital picture of the Q-patch. Clinical comparisons of the Q-patch to the standard Gibson- Cooke sweat test (GCST) method will also be conducted to ensure the accuracy of the Q-patch in a clinical setting. Through this endeavor, PolyChrome Medical, along with the University of Minnesota Cystic Fibrosis Center, intends for the Q-patch to replace the GCST method as the standard test for diagnosing cystic fibrosis. The ease of use and quick results of the Q-patch, together with its improved accuracy, will allow for a faster, more reliable diagnosis, which in turn will provide cystic fibrosis patients with earlier access to the therapy that they need. Early diagnosis in conjunction with aggressive therapy has proven to add significantly to the median life expectancy of CF patients.