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HelpTest Code PKUM Phenylalanine and Tyrosine, Plasma
Additional Codes
| Mayo | PKU |
| Epic ID | LAB3481 |
Specimen Type
PlasmaNecessary Information
1. Patient's age is required.
2. Include family history, clinical condition (asymptomatic or acute episode), diet, and drug therapy information.
Specimen Required
Patient Preparation:
Fasting: 8 hours, required; Infants should have specimen collected before next feeding
Collection Container/Tube:
Preferred: Green top (sodium heparin)
Acceptable: Green top (lithium heparin), lavender top (EDTA)
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions:
1. Centrifuge and aliquot plasma into a plastic vial.
2. Send plasma frozen.
Specimen Minimum Volume
0.1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Plasma | Frozen (preferred) | 14 days |
| Refrigerated | 14 days |
Transport frozen.
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Useful For
Monitoring effectiveness of dietary therapy in patients with hyperphenylalaninemia
Day(s) Performed
Monday through Friday
Report Available
2 to 4 daysReference Values
PHENYLALANINE
Premature: 98-213 nmol/mL
0-31 days: 38-137 nmol/mL
1-24 months: 31-75 nmol/mL
2-18 years: 26-91 nmol/mL
≥19 years: 35-85 nmol/mL
Conversion Formulas:
Result in mg/dL x 60.5=result in nmol/mL
Result in nmol/mL x 0.0165=result in mg/dL
TYROSINE
Premature: 147-420 nmol/mL
0-31 days: 55-147 nmol/mL
1-24 months: 22-108 nmol/mL
2-18 years: 24-115 nmol/mL
≥19 years: 34-112 nmol/mL
Conversion Formulas:
Result in mg/dL x 55.2=result in nmol/mL
Result in nmol/mL x 0.0181=result in mg/dL
CPT Code Information
84030 Phenylalanine
84510 Tyrosine
82542 (if appropriate for government payers)