Phenylalanine/Tyrosine, Plasma/Serum (Referred Out) - Saskatoon
Discipline
Biochemistry
Overview
Description
Ordering Recommendations
- Phenylalanine, Tyrosine, and the ratio will automatically be done on specimens that are monitoring the diet of known PKU patients
Testing Ordering Requirements
Forms Required
- Requisitions must have specific test indicated
- Miscellaneous Specimen Requisition Form #101878
- SHR Laboratory Medicine Community Laboratory Requisition Form #101064
- Acute Care Phlebotomy Requisition Form #10162
Alias
- Phenylketonuria(PKU)
- PKU diet monitoring
- Phenylalanine
- Tyrosine
- Phenylalanine/tyrosine ratio
Specimen Information
Specimen types accepted
- Plasma
- Serum
Specimen collection container
- Preferred Collection Container: Dark Green (Lithium Heparin) 4mL
- Alternative Collection Container:
Required volume
- Optimal Volume: 4.0 mL whole blood
- Minimum/Pediatric Volume: 2.0 mL whole blood
(Submitting the minimum volume makes it impossible to repeat the test or perform confirmatory/reflex testing. In some situations, a minimum volume may require a second collection)
Transport and stability
- Keep at 2 – 8 °C
- Send to referral laboratory refrigerated
Rejection criteria
- Specimens received where the proper collection protocols were not followed
- Pathology and Laboratory Medicine Acceptance and Rejection Criteria
Testing Information
Relevant clinical history
- Family history
- Must include diagnosis and/or patient symptoms on the requisition
Clinical interpretation
- Result interpretation should be correlated with clinical and other laboratory findings.
Performance
Days/times performed
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Maximum laboratory time
Results Reporting
- Routine results within 5 days
Other information
Additional Comments
- Follow up for newborn screening (PKU)
- Used in diet monitoring of PKU and Tyrosinemia
Last Updated: October 9, 2024