A Point-Of-Care Device for Phenylalanine Determination
Grant Number: 2 R44 GM126593-02A1
Grant Agency and Type: NIH NIGMS, Phase II SBIR
Principal Investigator: Robert Harper
Disease Indication: Phenylketonuria
Phenylketonuria (PKU) is an inherited disorder that increases the levels of L-phenylalanine (Phe) in the blood. Without proper monitoring and treatment, patients can develop permanent intellectual disabilities, seizures, behavioral problems, and psychiatric disorders. In Vitro Diagnostic Solutions (IVDS) proposes to develop the first point-of-care (POC) test, the PKU Now, for the determination of Phe from a finger or heel-stick sample. Like the glucose model, the PKU NowTM System is comprised of a hand-held meter and test strip. The PKU Now will be used as both a home monitoring device and a diagnostic device in countries that do not currently offer newborn screening. In Phase II, we propose to test a range of commercially available diaphorase and phenylalanine dehydrogenases (PheDHs) and select the pair that provides the greatest delta (optimally 45-47 units %R) and the shortest read time (ideally under 3 minutes). The diaphorase is critical for the stability and rate of color development of the reagent. It must (1) have a high degree of activity in conjunction with PheDH; (2) have specificity for B-NAD+; and (3) provide long-term reagent stability (20-25°C for 18 months).
The PKU Now will provide real-time Phe levels, allowing parents and caregivers to promptly adjust their diets to help maintain optimal phenylalanine levels. In Vitro Diagnostic Solutions (IVDS) has developed a prototype POC test, in which Phe can be quantified from a 20-microliter sample. “PKU Now” will be the only point-of-care testing device (POCT) that will allow the accurate measurement of L-phenylalanine (Phe) levels from a finger or heel-stick sample. The point-of-care test, the “PKU Now” will be used as a home monitoring device for PKU patients and for diagnostic testing. The PKU Now will provide immediate feedback of whole blood Phe concentration, allowing for stricter dietary compliance, improve the quality of life, and reduce healthcare costs.