title: Optimization of an HPLC method for phenylalanine and tyrosine quantization in dried blood spot.
abstract: OBJECTIVE
  Patients affected by Phenylketonuria (PKU) require lifelong management based on phenylalanine (Phe) and tyrosine (Tyr) restricted intake or tetrahydrobiopterin (BH4) administration. Frequent monitoring of blood concentration of both amino acids during treatment is the key point for clinicians to achieve the best long-term neuropsychological outcome.
  
  
  RESULTS
  The present study develops and validates a rapid and simple method for Phe and Tyr quantization in dried blood spot (DBS) since this specimen has the advantage of being low invasive, easily withdrawn even at home and stable if mail-delivered. The validation studies showed the robustness of the method.
  
  
  CONCLUSIONS
  Serum and DBS samples from PKU patients were analyzed and compared, finding a good correlation of Phe and Tyr concentrations between the two different matrixes.
authors.affiliation: Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Pecce
authors.forename: Emanuela
authors.initials: E
authors.lastname: Scolamiero
authors.forename: Laura
authors.initials: L
authors.lastname: Ingenito
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Parenti
authors.forename: Margherita
authors.initials: M
authors.lastname: Ruoppolo
mesh_terms: D000293:Adolescent; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D059788:Dried Blood Spot Testing / Q000379:methods*; D006801:Humans; D010649:Phenylalanine / Q000097:blood*; D010661:Phenylketonurias / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014443:Tyrosine / Q000097:blood*; D055815:Young Adult
chemical_list: D014443:Tyrosine; D010649:Phenylalanine
keywords: DBS; Dried blood spot; HCl; HPA; HPLC; Hyperphenylalaninemia; LOD; LOQ; OPA-3-MPA; PAH; PKU; Phe; Phenylalanine; S/N; Tyr; Tyrosine; dried blood spot; high-performance liquid chromatography; hydrochloric acid; hyperphenylalaninemia; limit of detection; limit of quantitation; o-phthaldehyde-3-mercaptopropionic acid; phenylalanine; phenylalanine hydroxylase; phenylketonuria; signal-to-noise ratio; tyrosine