{"id":"phenylalanine","name":"Phenylalanine","shortName":"Phenylalanine","aliases":["Phenylalanine, Plasma","Phenylalanine, Quantitative, Plasma","Phenylalanine, Serum","Plasma Phenylalanine","Blood Phenylalanine","Phenylalanine Level","Phenylalanine (Phe)","Phe","L-Phenylalanine"],"abbreviations":["Phe"],"loinc":[{"code":"14875-9","primary":true},{"code":"2765-6","primary":false}],"specimen":"plasma","units":[{"ucum":"umol/L","display":"µmol/L"},{"ucum":"mg/dL","display":"mg/dL"}],"referenceRanges":[{"population":"19+","low":35,"high":85,"unit":"umol/L","unitDisplay":"µmol/L","note":"Mayo Clinic Laboratories adult interval, fasting plasma (Mayo prints nmol/mL, which equals µmol/L). ARUP prints 30 to 82 µmol/L from age 1 year. People with PKU follow a treatment goal instead: the ACMG guideline aims for 120 to 360 µmol/L for life, and the European guideline aims for 120 to 600 µmol/L after age 12.","sources":[{"title":"Phenylalanine and Tyrosine, Plasma (test PKU)","url":"https://www.mayocliniclabs.com/test-catalog/overview/8380","publisher":"Mayo Clinic Laboratories"},{"title":"Phenylalanine and Tyrosine (test 0080336)","url":"https://ltd.aruplab.com/Tests/Pub/0080336","publisher":"ARUP Laboratories"},{"title":"Phenylalanine hydroxylase deficiency: diagnosis and management guideline","url":"https://pubmed.ncbi.nlm.nih.gov/24385074/","publisher":"Genetics in Medicine (American College of Medical Genetics and Genomics)","year":2014},{"title":"The complete European guidelines on phenylketonuria: diagnosis and treatment","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC5639803/","publisher":"Orphanet Journal of Rare Diseases","year":2017}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"Measures phenylalanine, an amino acid from protein foods, and is mostly used to follow phenylketonuria (PKU), which is usually found at birth.","url":"https://bloodtesttracker.com/markers/phenylalanine","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}