Serum Albumin (Albumin)
Albumin is the most abundant circulating plasma protein synthesized solely by hepatocytes. It maintains intravascular oncotic pressure and serves as the primary transport vehicle for hormones, fatty acids, and drugs.
Standard vs. Optimal Reference Rangesg/dL
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.
3.5 - 5.5 g/dL
General reference distribution across unselected commercial populations.
4.5 - 5.0 g/dL
Concentration target associated with minimal all-cause cardiometabolic mortality.
Molecular Mechanism & Clinical Purpose
Albumin accounts for ~75% of plasma colloid oncotic pressure. It contains a single free cysteine residue (Cys34) that serves as the predominant extracellular antioxidant scavenger of reactive oxygen and nitrogen species.
Differential Diagnosis
Elevated Levels (Albumin High)
- •Intravascular volume depletion / Dehydration (hemoconcentration)
Low Levels (Albumin Low)
- •Hepatic cirrhosis (impaired protein synthesis)
- •Systemic inflammation (albumin is a negative acute-phase reactant)
- •Nephrotic syndrome (urinary protein loss)
- •Protein-losing enteropathy / Malnutrition
Technical Reference & Deep Dive
Biochemistry & Enzymatic Pathways
Longevity Risk Architecture & Epidemiology
Pre-Analytical Caveats & Diagnostic Workup
Pre-Analytical Considerations:
A 12-hour overnight fast is recommended, especially if assessing biliary markers or lipid-associated hepatic enzymes. Complete abstinence from ethanol for at least 48 to 72 hours prior to testing is mandatory to prevent enzyme induction. Avoid strenuous unaccustomed weightlifting for 48 hours prior, which can release muscular transaminases and elevate AST/ALT.
Reflexive Testing Protocol:
- Comprehensive Hepatic Viral Panel (Hepatitis A IgM, HBsAg, HBcAb, HCV antibody with reflex PCR)
- Vibration-Controlled Transient Elastography (FibroScan) or Magnetic Resonance Elastography to quantify hepatic fat and fibrosis
- Serum Ferritin and Total Iron-Binding Capacity (TIBC) to screen for hereditary hemochromatosis
- Autoimmune Liver Disease Serology (Anti-Nuclear Antibodies, Anti-Smooth Muscle Antibodies, Anti-Mitochondrial Antibodies)
- Abdominal Right Upper Quadrant Ultrasound to assess hepatic parenchyma, biliary ducts, and portal vein flow
Clinical Citations & Primary Literature (1)
- [1]Serum Albumin and Longevity: An Integrative Review of Biomarkers of Aging - Cell Metabolism (2022). PMID: 35012398
Associated Longevity Guides & Clinical Calculators
Medicine 3.0Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Serum Albumin (Albumin) into overall healthspan optimization.