2Bell CJ. Newborn screening quality assurance program summary report., inborn errors of metabolism [J]. CDC, 2005,16(1 ): 12-13.
3Levy PA,Miller JB,Shapira E. The advantage of phenylalanine to tyrosine ratio for the early detection of phenylketonuria [J]. Clin Chim Acta, 1998, 270 (2) : 177-181.
4Luciana M,Sullivan J, Nelson CA. Associations between phenylalanine-to-tyrosine ratios and performance on tests of neuropsychological function in adolescents treated early and continuously for phenylketonuria[J]. Child Dev, 2001,72(6) : 1637-1652.
5Tcherkas YV, Kartsova LA, Krasnova IN. Analysis of amino acids in human serum by isocratic reversedphase high-performapce liquid chromatography with electrochemical detection [J]. J Chromatogr A, 2001, 913(1-2) : 303-308.