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Biomarker Encyclopedia

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Home/Biomarkers/Metabolic & Glycemic Control/Phe
Metabolic & Glycemic ControlPhenylketonuria & PAH Flux

Serum Phenylalanine (Phe)

Essential aromatic amino acid converted to L-tyrosine by hepatic phenylalanine hydroxylase (PAH) in the presence of tetrahydrobiopterin (BH4).

Standard Range30 - 80 umol/L (0.5 - 1.3 mg/dL)
Optimal Longevity35 - 70 umol/L
Measurement Unitumol/L
Organ SystemPhenylketonuria & PAH Flux
Routine Panels:Newborn Metabolic ScreenPKU Monitoring Profile

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.

Interactive Range Analyzer
Unit: umol/L
umol/L
Presets:
21 umol/LOptimal Zone Target108 umol/L
Optimal Longevity Zone(52.5 umol/L)

Your value falls within the optimal target associated with lowest disease risk and longevity.

Standard Reference Interval

30 - 80 umol/L (0.5 - 1.3 mg/dL)

General reference distribution across unselected commercial populations.

Optimal Longevity Target

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
At the molecular level, Serum Phenylalanine (Phe) plays an essential physiological role in phenylketonuria & pah flux. Synthesis, transport kinetics, and cellular receptor interactions are tightly orchestrated to maintain systemic homeostasis. Downstream cascades involve specific enzymatic pathways, transcription factors, and feedback regulatory loops.
Longevity Risk Architecture & Epidemiology
Primary diagnostic and therapeutic monitoring biomarker for Phenylketonuria (PKU), preventing irreversible intellectual disability.
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
Common Panels:Newborn Metabolic ScreenPKU Monitoring Profile
View All Panels

Associated Longevity Guides & Clinical Calculators

Medicine 3.0

Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Serum Phenylalanine (Phe) into overall healthspan optimization.

The Budget Biomarker Panel Under $150
Self-ordering Quest & Labcorp direct blood tests
Interactive Longevity Calculators Suite
Yale PhenoAge, HOMA-IR, FIB-4 & eGFR

Related Metabolic & Glycemic Control Biomarkers

High-Sensitivity C-Reactive Protein
hs-CRP · < 0.5 mg/L
Serum Creatinine
Cr · 0.8 - 1.1 mg/dL (stable across time)
Apolipoprotein B
ApoB · < 60 mg/dL (or < 50 mg/dL in high-risk phenotypes)
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