Phenylalanine/Tyrosine

Laboratory Fee Schedule
Procedure #:  BZZ0003A 
CPT:  84030, 84510

Synonym(s):Phenylketonuria (PKU) Dietary Monitoring
Requisition FormG-1B
Test DescriptionTest to detect concentrations of the amino acids phenylalanine and tyrosine for phenylketonuria (PKU) dietary monitoring.
Pre-Approval NeededN/A
Supplemental Information RequiredN/A
Supplemental Form(s)N/A
Performed on Specimens from (sources)Human
Sample/Specimen Type for TestingDried whole blood on DSHS approved filter paper card.
Minimum Volume/Size RequiredTwo ½ inch dried blood spots
Storage/Preservation Prior to Shipping
  • Allow card to dry thoroughly at room temperature in a horizontal position for at least 3 hours. Do NOT allow specimen to touch any surface.
  • Keep specimen away from heat and direct sunlight.
  • Cover dried specimen with attached flap.
Transport MediumN/A
Specimen Labeling
  • Two patient-specific identifiers required (e.g., patient full name, date of birth)
  • Identifiers on specimen must match submission form exactly
Shipping and Specimen Handling Requirements

Ship all specimens according to Dangerous Good Regulations, IATA, and/or CFR 49. 

Must include one completed G-1B form per specimen.

DRIED FILTER PAPER BLOOD SPECIMENS

  • U.S. Postal regulations require Double containment of dried blood filter paper specimens. Ensure specimens are thoroughly dried prior to placing in envelope.
  • 1st containment: Use the attached wrap-around cover with printed universal biohazard symbol. Do not put biohazard labels on outside of envelope.
  • 2nd containment:  Place dried filter paper blood specimen in an envelope that is not hermetically sealed. Do not put specimens in plastic bags.
  • Ship as soon as possible; within 24hrs of collection.
  • Avoid temperatures greater than 100°F.
MethodTandem Mass Spectrometry
Turn-around TimeWithin 4 working days after receipt of specimen
Interferences/LimitationsAlcohol swab with a topical pain killer such as benzocaine can interfere with the testing,
Common Causes for Rejection
  • Use of expired specimen collection device
  • No date of collection provided.
  • Missing/invalid patient demographic information
  • Specimen is too old upon receipt (received more than 21 days following collection)
  • No blood samples received with request form.
  • Insufficient blood has been submitted.
  • Specimen is contaminated or discolored.
  • Serum separation due to improper drying or collection

 

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Additional Information

Reference Range:

Phenylalanine values less than 4.0 mg/dL are normal. Tyrosine values less than 3.0 mg/dL are normal.