Conflicts of Interest The authors declare no conflicts of interest. References 1, “Der Blutzucker,” Zeitschrift Für Analytische Chemie 52, no. 7 (1913): 521–523. 2 and , “A Simple Phenylalanine Method for Detecting Phenylketonuria in Large Populations of Newborn Infants,” Pediatrics 32, no. 3 (1963): 338–343, https://doi.org/10.1542/peds.32.3.338. 3, “Dried Blood Spots: Analysis and Applications,” Analytical Chemistry 85, no. 2 (2013): 779–789, https://doi.org/10.1021/ac303205m.
