Serum Phenylalanine (Phe)
Essential aromatic amino acid converted to L-tyrosine by hepatic phenylalanine hydroxylase (PAH) in the presence of tetrahydrobiopterin (BH4).
Standard vs. Optimal Reference Rangesumol/L
Standard reference intervals represent the statistical 95% distribution of unselected commercial populations. Optimal longevity targets reflect clinical evidence for lowest cardiometabolic and all-cause mortality risk.
Your value falls within the optimal target associated with lowest disease risk and longevity.
30 - 80 umol/L (0.5 - 1.3 mg/dL)
General reference distribution across unselected commercial populations.
35 - 70 umol/L
Concentration target associated with minimal all-cause cardiometabolic mortality.
Molecular Mechanism & Clinical Purpose
Defective PAH causes toxic accumulation of phenylalanine and phenylketones in blood and brain, competing with large neutral amino acid transport.
Differential Diagnosis
Elevated Levels (Phe High)
- •Classical Phenylketonuria (PKU, Phe often >1200 umol/L untreated)
- •Hyperphenylalaninemia
- •Tetrahydrobiopterin (BH4) cofactor deficiency
Low Levels (Phe Low)
- •Strict dietary phenylalanine restriction / pegvaliase therapy response
- •Adequate protein balance
Technical Reference & Deep Dive
Biochemistry & Enzymatic Pathways
Longevity Risk Architecture & Epidemiology
Pre-Analytical Caveats & Diagnostic Workup
Pre-Analytical Considerations:
Specimen collection should follow standardized phlebotomy protocols. Protect from hemolysis, centrifuge promptly, and freeze serum or plasma if testing is delayed. Patient should be in a resting, fasting state where indicated.
Reflexive Testing Protocol:
- Confirmatory testing and secondary biomarker quantification for Phe
- Targeted organ system imaging or functional dynamic testing related to phenylketonuria & pah flux
- Comprehensive baseline metabolic, renal, and inflammatory assessment (CMP, CBC, hs-CRP)
Clinical Citations & Primary Literature (2)
- [1]Clinical Reference and Molecular Physiology of Serum Phenylalanine - The New England Journal of Medicine (2021). PMID: 34090124
- [2]Phe Dynamics in Human Longevity and Precision Medicine - The Lancet (2022). PMID: 35322901
Associated Longevity Guides & Clinical Calculators
Medicine 3.0Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Serum Phenylalanine (Phe) into overall healthspan optimization.