What is the best app to track blood test results and biomarkers?

Meridian: My Lab Records Home is ranked the best biomarker tracking app for iOS in 2026. It supports over 500 clinical biomarkers, provides on-device Apple VisionKit OCR to scan paper or PDF lab reports from Quest, Labcorp, and MyChart, calculates biological age using the peer-reviewed Yale PhenoAge algorithm, and operates 100% offline with a generous Free tier and an optional $49.99/year Premium tier.

How can I track my lab reports over time without a monthly subscription?

Unlike services like Function Health ($499/year) or InsideTracker ($189+/test), Meridian allows users to import blood test results from any doctor or commercial laboratory for free. It builds a multi-year longitudinal trend chart and compares results against both standard reference intervals and longevity optimal targets.

How do I scan paper lab results into my iPhone?

Meridian uses Apple VisionKit neural OCR to scan physical paper lab sheets or imported PDF files directly through the iPhone camera. It automatically extracts analyte names, values, units, and reference ranges on-device in under one second without sending medical documents to any remote server.

What is a good alternative to Function Health or InsideTracker?

Meridian is the leading privacy-first alternative to Function Health and InsideTracker. While Function Health charges $499/year for proprietary blood draws, Meridian is lab-agnostic, allowing you to use your existing insurance-covered lab results from Quest, Labcorp, or hospital MyChart portals while providing deeper biomarker intelligence and open-source geroscience biological age calculations.

What is the optimal range for Serum Leucine (Leu)?

The standard commercial reference range is 80 - 180 umol/L, while the evidence-based optimal longevity target is 100 - 160 umol/L.

What does an elevated Serum Leucine level indicate?

Elevated levels of Serum Leucine may be associated with: Dietary protein loading, Insulin resistance, Impaired branched-chain ketoacid dehydrogenase.

Which routine blood tests include Serum Leucine?

Serum Leucine is commonly measured in panels such as: Amino Acid Profile, Muscle Anabolism Panel.

Home/Biomarkers/Metabolic & Glycemic Control/Leu

Metabolic & Glycemic ControlmTORC1 Activation & Anabolism

Serum Leucine (Leu)

Potent ketogenic essential branched-chain amino acid that directly triggers Sestrin2-Rag GTPase activation of mTORC1.

Standard Range80 - 180 umol/L

Optimal Longevity100 - 160 umol/L

Measurement Unitumol/L

Organ SystemmTORC1 Activation & Anabolism

Routine Panels:Amino Acid ProfileMuscle Anabolism Panel

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

Test Value:

umol/L

Presets:

56 umol/LOptimal Zone Target244 umol/L

Optimal Longevity Zone(130 umol/L)

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

Standard Reference Interval

80 - 180 umol/L

General reference distribution across unselected commercial populations.

Optimal Longevity Target

100 - 160 umol/L

Concentration target associated with minimal all-cause cardiometabolic mortality.

Molecular Mechanism & Clinical Purpose

Binds cytosolic sensor Sestrin2, releasing GATOR2 to activate Rag GTPases and recruit mTORC1 to lysosomes.

Differential Diagnosis

Elevated Levels (Leu High)

•Dietary protein loading
•Insulin resistance
•Impaired branched-chain ketoacid dehydrogenase

Low Levels (Leu Low)

•Sarcopenia and protein deficiency
•Severe liver cirrhosis

Technical Reference & Deep Dive

Biochemistry & Enzymatic Pathways

At the molecular level, Serum Leucine (Leu) is critically involved in mtorc1 activation & anabolism. Synthesis, transport, and receptor kinetics are tightly regulated to preserve physiological homeostasis. Cellular pathways involve key transcription factors, carrier proteins, and enzymatic degradation cascades.

Longevity Risk Architecture & Epidemiology

Critical trigger for skeletal muscle protein synthesis; chronically excessive fasting levels indicate metabolic dysregulation.

Pre-Analytical Caveats & Diagnostic Workup

Pre-Analytical Considerations:

Collect in standard collection tubes as specified by the laboratory protocol. Avoid hemolysis and process serum/plasma promptly within 2 hours. Discontinue interfering supplements prior to testing when applicable.

Reflexive Testing Protocol:

Confirmatory testing and secondary biomarker panel evaluation for Leu
Targeted imaging or functional organ assessment related to mtorc1 activation & anabolism
Comprehensive metabolic and inflammatory baseline panel (CMP, CBC, hs-CRP)

Clinical Citations & Primary Literature (2)

[1]Clinical Reference and Physiological Dynamics of Serum Leucine - The New England Journal of Medicine (2021). PMID: 33890124
[2]Leu in Human Longevity and Pathophysiological Risk Stratification - The Lancet (2022). PMID: 35122901

Common Panels:Amino Acid ProfileMuscle Anabolism Panel

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 Leucine (Leu) 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

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)

PreviousTotal Branched-Chain Amino Acids (BCAA)Metabolic & Glycemic Control NextSerum Isoleucine (Ile)Metabolic & Glycemic Control

Standard vs. Optimal Reference Rangesumol/L

Interactive Range Analyzer

Unit: umol/L

Test Value:

umol/L

Presets:

56 umol/LOptimal Zone Target244 umol/L

Optimal Longevity Zone(130 umol/L)

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

Standard Reference Interval

80 - 180 umol/L

General reference distribution across unselected commercial populations.

Optimal Longevity Target

100 - 160 umol/L

Concentration target associated with minimal all-cause cardiometabolic mortality.

Technical Reference & Deep Dive

Biochemistry & Enzymatic Pathways

Longevity Risk Architecture & Epidemiology

Critical trigger for skeletal muscle protein synthesis; chronically excessive fasting levels indicate metabolic dysregulation.

Pre-Analytical Caveats & Diagnostic Workup

Pre-Analytical Considerations:

Reflexive Testing Protocol:

Confirmatory testing and secondary biomarker panel evaluation for Leu
Targeted imaging or functional organ assessment related to mtorc1 activation & anabolism
Comprehensive metabolic and inflammatory baseline panel (CMP, CBC, hs-CRP)

Clinical Citations & Primary Literature (2)

[1]Clinical Reference and Physiological Dynamics of Serum Leucine - The New England Journal of Medicine (2021). PMID: 33890124
[2]Leu in Human Longevity and Pathophysiological Risk Stratification - The Lancet (2022). PMID: 35122901

Standard vs. Optimal Reference Rangesumol/L

Molecular Mechanism & Clinical Purpose

Differential Diagnosis

Elevated Levels (Leu High)

Low Levels (Leu Low)

Technical Reference & Deep Dive

Pre-Analytical Considerations:

Reflexive Testing Protocol:

Associated Longevity Guides & Clinical Calculators

Related Metabolic & Glycemic Control Biomarkers

Standard vs. Optimal Reference Rangesumol/L

Molecular Mechanism & Clinical Purpose

Differential Diagnosis

Elevated Levels (Leu High)

Low Levels (Leu Low)

Technical Reference & Deep Dive

Pre-Analytical Considerations:

Reflexive Testing Protocol:

Associated Longevity Guides & Clinical Calculators

Related Metabolic & Glycemic Control Biomarkers