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

Turnaround Time

  • 1-3 days

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