Testing of Four Home Phenylalanine Monitoring Prototype Devices

A real time, point-of-care and home phenylalanine monitoring system would provide patients with quick results and feedback. Home monitoring devices' phenylalanine measurements will be compared to the current gold-standard measurement of phenylalanine (plasma concentration) in four subjects with PKU and one control subject. The study will enroll subjects with different baseline phenylalanine concentrations (i.e., patients with poor to good metabolic control, assessed by comparing current phenylalanine concentrations to established treatment ranges).

For each prototype device, three separate measurements of phenylalanine per subject will be performed. Three prototype devices require whole blood, thus 1 teaspoon (approximately 4mL) of whole blood will be collected through venipuncture and blood spots will be used to conduct tests. One prototype requires capillary blood to be collected through a fingerstick, and will require three blood spots from the stick. A single plasma amino acid analysis for each participant will also be performed using leftover whole blood from the 4mL blood draw through quantitative ion exchange chromatography, reported as micromoles/L.