A PKU screening test measures the amount of a protein called phenylalanine (Phe) in a sample of a newborn's blood. Phe is in all foods that contain protein such as milk, meats, and nuts. It's also in an artificial sweetener called aspartame. If a newborn has high levels of Phe in their blood, it could mean that they have phenylketonuria (PKU).
A PKU test is used to see if a newborn has high blood levels of Phe in their blood. Though PKU is rare, all newborns in the United States are tested for it.
Source: MedlinePlus, U.S. National Library of Medicine
Normal range
- ≤ 1 mo
- 38–137 nmol/mL
- ≤ 30 d
- 30–95 umol/L
- ≤ null d
- 98–213 nmol/mL
- 1 y+
- 30–82 umol/L
- 19 y+
- 35–85 nmol/mL
- 2 y – 18 y
- 26–91 nmol/mL
- 30 d – 11 mo
- 30–90 umol/L
- 30 d – 2 y
- 31–75 nmol/mL
Ranges from ARUP Laboratories Test Directory, Mayo Clinic Laboratories (Pediatric Test Catalog).
All 13 source ranges
What an abnormal result can be associated with
- A high result
- Hyperphenylalaninemia
- A low result
- Hypophenylalaninemia
Associations from LOINC2HPO (Human Phenotype Ontology). This is reference information, not a diagnosis — only a clinician can interpret your result in context.
Details
- Sample
- Serum or plasma · LOINC
- Part of
- Amino acids panel
- Listed under
- Phenylketonuria
- Code
- LOINC 14875-9 · umol/L
- Also known as
- Phe, PPA