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Biomarker Encyclopedia

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Home/Biomarkers/Cardiovascular & Lipidology/ApoA1
Cardiovascular & LipidologyAnti-Atherogenic Reverse Cholesterol Transport

Apolipoprotein A1 (ApoA1)

Apolipoprotein A1 is the principal protein constituent of HDL particles, orchestrating cellular cholesterol efflux and possessing antioxidant, anti-inflammatory, and antithrombotic properties.

Standard Range115 - 190 mg/dL (Male), 115 - 220 mg/dL (Female)
Optimal Longevity140 - 180 mg/dL
Measurement Unitmg/dL
Organ SystemAnti-Atherogenic Reverse Cholesterol Transport
Routine Panels:Apolipoprotein PanelCardio IQ®

Standard vs. Optimal Reference Rangesmg/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.

Interactive Range Analyzer
Unit: mg/dL
mg/dL
Presets:
80 mg/dLOptimal Zone Target257 mg/dL
Optimal Longevity Zone(160 mg/dL)

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

Standard Reference Interval

115 - 190 mg/dL (Male), 115 - 220 mg/dL (Female)

General reference distribution across unselected commercial populations.

Optimal Longevity Target

140 - 180 mg/dL

Concentration target associated with minimal all-cause cardiometabolic mortality.

Molecular Mechanism & Clinical Purpose

ApoA1 interacts with ABCA1 transporters on lipid-laden macrophages, initiating the removal of excess cholesterol and activating LCAT to convert free cholesterol to cholesteryl esters for transport to the liver.

Differential Diagnosis

Elevated Levels (ApoA1 High)

  • •Estrogen therapy
  • •Regular aerobic exercise
  • •Familial hyperalphalipoproteinemia

Low Levels (ApoA1 Low)

  • •Tangier disease
  • •Severe coronary artery disease
  • •Smoking and metabolic syndrome
  • •Uncontrolled diabetes

Technical Reference & Deep Dive

Biochemistry & Enzymatic Pathways
At the cellular and molecular level, Apolipoprotein A1 (ApoA1) is central to lipoprotein particle assembly, apolipoprotein-receptor interactions, and subendothelial retention kinetics. Synthesis occurs primarily within hepatocytes and enterocytes, regulated by transcriptional co-activators (such as SREBP-2 and PPAR-alpha) and microsomal triglyceride transfer protein (MTP). Particle clearance is mediated through high-affinity endocytic receptors (including LDLR, LRP1, and scavenger receptors SR-B1). Circulating plasma half-life ranges from 2 to 4 days. Transcytosis across vascular endothelial cell monolayers occurs via scavenger receptor class B type 1 (SR-B1) and activin-like kinase 1 (ALK1), trapping particles within the subendothelial proteoglycan matrix where oxidative modification initiates foam cell formation.
Longevity Risk Architecture & Epidemiology
Higher circulating ApoA1 levels correlate with preserved endothelial vasodilation and reduced cardiovascular event rates.
Pre-Analytical Caveats & Diagnostic Workup

Pre-Analytical Considerations:

Standard testing requires a 10 to 12 hour overnight fast to minimize postprandial chylomicron interference, although ApoA1 direct immunoassay is less sensitive to prandial state than calculated LDL-C. Avoid strenuous high-intensity exercise 24 hours prior to blood draw. Serum separator tubes (SST) or EDTA plasma should be centrifuged within 2 hours. High-dose biotin (>5 mg/day) supplementation may interfere with competitive streptavidin-biotin immunoassays, requiring a 48-hour washout period.

Reflexive Testing Protocol:

  • Advanced Lipoprotein Particle Quantification (NMR spectroscopy or ion mobility LDL-P)
  • Lipoprotein(a) [Lp(a)] baseline evaluation for genetic cardiovascular risk stratification
  • Coronary Artery Calcium (CAC) score via non-contrast cardiac CT to evaluate calcified plaque burden
  • High-sensitivity C-Reactive Protein (hs-CRP) to assess systemic vascular inflammatory tone
  • Carotid intima-media thickness (CIMT) duplex ultrasound to assess subclinical atherosclerosis
Clinical Citations & Primary Literature (1)
  • [1]Apolipoprotein A-I and Cardiovascular Risk Protection - Nature Reviews Cardiology (2021). PMID: 34188710
Common Panels:Apolipoprotein PanelCardio IQ®
View All Panels

Associated Longevity Guides & Clinical Calculators

Medicine 3.0

Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Apolipoprotein A1 (ApoA1) 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 Cardiovascular & Lipidology Biomarkers

High-Density Lipoprotein Cholesterol
HDL-C · 50 - 70 mg/dL
Apolipoprotein B
ApoB · < 60 mg/dL (or < 50 mg/dL in high-risk phenotypes)
ApoB to ApoA1 Ratio
ApoB/ApoA1 · < 0.50
PreviousOxidized Low-Density Lipoprotein (oxLDL)Cardiovascular & LipidologyNextApoB to ApoA1 Ratio (ApoB/ApoA1)Cardiovascular & Lipidology