Conversion of a laboratory-based test for phenylalanine detection to a simple paper-based format and implications for PKU screening in low-resource settings.

Laboratory-based testing does not reach many individuals in lower-resource settings who could benefit from access to appropriate tests for diagnosis and therapy. A critical issue is laboratory-based testing often requires an environment with a high level of resources and supporting infrastructure that is not available in many areas of the world. The current report describes the conversion of a laboratory-based test for phenylalanine detection to a simple paper-based test appropriate for use in low-resource settings. The paper-based test is easy to operate, with all reagents stored dry on the card, is compatible with visible detection for clinically relevant concentrations of phenylalanine, and has a time to result of 10 minutes. Next steps for test development are discussed in the context of the potential for the paper-based Phe test to be used as a newborn PKU screening test in settings that are not well served by existing screening approaches.