Phenylalanine and Tyrosine


Related Gene(s): PAH

Phe and Tyr are selectively evaluated in dried blood spot samples to monitor dietary treatment in patients with phenylketonuria (PKU). Phe and Tyr are measured by a liquid chromatography and tandem mass spectrometry (LC-MS/MS) method.

Specimen Requirements

  • Peripheral blood: Collect from finger prick or heel stick spotted on a special filter paper to make 2 full circles and air dry. Please note that complete saturation of blood in the marked circle is necessary. Blood should be sampled fasting or 4 hours postprandial. Sampling for infants should occur just before next feeding

Ordering Information


  • Ship at room temperature
  • Ship to:
    62 Southfield Ave, Stamford, CT 06902
    Phone: 800-298-6470 / Fax: 646-859-6870


Turnaround Time

  • 1-3 days


Related Tests


Biochemical Genetic Testing Requisition