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Test Code LAB5336 Phenylalanine (PKU), Quantitative, Blood

Performing Laboratory

St. Louis Children's Hospital

Last Reviewed

November 2024

Lab Dept

Core Lab

Specimen Requirements

Specimen Type: Blood

Container/Tube

Preferred: Mint green-top (lithium heparin) Vacutainer

Acceptable: green SAMPLETTE/MICROTAINER; Plain, Red-top Vacutainer; Gold/Red SST gel Vacutainer or Dark Green-top (NaHep) Vacutaine

Collection Volume: 2.0 mL (minimum 0.5 mL)

Patient Preparation: None

Sample Rejection: Mislabeled or unlabeled specimens.

Special Instructions: Send to lab promptly.

Interpretive

Reference Range:

<1 month: 30-120 micmol/L

≥ 1 month: 30-90 micmol/L

Critical Values: None established

Limitations: NA

Methodology: Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Test Classification: This test was developed and its performance characteristics determined by St. Louis Children's Hospital Clinical Laboratory. It has not been cleared or approved by the U.S. Food and Drug Administration.

Additional Information

For SLCH Laboratory use only

Lab Processing instructions: Centrifuge specimen to separate and aliquot sample into a plastic conical tube (label as serum if collected in Red top or gold/red tube). Place aliquot tube in freezer. (see note below)

Processed Volume: 0.3 mL plasma/serum

Analyte Stability:
Ambient (whole blood or processed): 5 days

PROCESSED

Refrigerated: 1 week

Frozen: Indefinitely

Notes: Specimens coming from outside facilities that are in aliquot containers should be kept in original container sent when given to Met. Genetics lab (put in freezer).

General Information

EPIC order name: Phenylalanine  (EPIC Test # LAB5336)

Cerner order name: PKU

CPT Codes: 84030

LOINC Value: 14875-9

Synonyms: 
 

Logistics

Test Availability: Daily

Days set up: Monday-Friday

Cut-off time: Varies; batched once per day in a.m.
Turnaround Time: 24-72 hours

Lab Testing Section: Metabolic Genetics