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 Diamine Oxidase (DAO)?

The standard commercial reference range is >10.0 U/mL, while the evidence-based optimal longevity target is >14.0 U/mL.

What does an elevated Serum Diamine Oxidase level indicate?

Elevated levels of Serum Diamine Oxidase may be associated with: Normal histamine catabolic capacity, Intact mature enterocyte brush border.

Which routine blood tests include Serum Diamine Oxidase?

Serum Diamine Oxidase is commonly measured in panels such as: Histamine Intolerance Profile.

Home/Biomarkers/Immunology & Longevity Clocks/DAO

Immunology & Longevity ClocksHistamine Degradation Capacity

Serum Diamine Oxidase (DAO)

Secretory enzyme produced by mature intestinal enterocytes that catabolizes extracellular ingested histamine.

Standard Range>10.0 U/mL

Optimal Longevity>14.0 U/mL

Measurement UnitU/mL

Organ SystemHistamine Degradation Capacity

Routine Panels:Histamine Intolerance Profile

Standard vs. Optimal Reference RangesU/mL

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: U/mL

Test Value:

U/mL

Presets:

7 U/mLOptimal Zone Target38 U/mL

Optimal Longevity Zone(21 U/mL)

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

Standard Reference Interval

>10.0 U/mL

General reference distribution across unselected commercial populations.

Optimal Longevity Target

>14.0 U/mL

Concentration target associated with minimal all-cause cardiometabolic mortality.

Molecular Mechanism & Clinical Purpose

Deaminates dietary and microbial histamine into imidazole-4-acetaldehyde, preventing systemic absorption.

Differential Diagnosis

Elevated Levels (DAO High)

•Normal histamine catabolic capacity
•Intact mature enterocyte brush border

Low Levels (DAO Low)

•Histamine intolerance syndrome
•Enterocyte mucosal damage (Crohn, Celiac)
•DAO-inhibiting medication use (NSAIDs, alcohol)

Technical Reference & Deep Dive

Biochemistry & Enzymatic Pathways

At the molecular level, Serum Diamine Oxidase (DAO) is critically involved in histamine degradation capacity. 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

Deficiency drives histamine intolerance syndrome, presenting with postprandial flushing, headaches, and palpitations.

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 DAO
Targeted imaging or functional organ assessment related to histamine degradation capacity
Comprehensive metabolic and inflammatory baseline panel (CMP, CBC, hs-CRP)

Clinical Citations & Primary Literature (2)

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

Common Panels:Histamine Intolerance 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 Diamine Oxidase (DAO) 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)

PreviousFecal / Serum Zonulin (Zonulin)Immunology & Longevity Clocks NextFecal Secretory IgA (sIgA)Immunology & Longevity Clocks

Standard vs. Optimal Reference RangesU/mL

Interactive Range Analyzer

Unit: U/mL

Test Value:

U/mL

Presets:

7 U/mLOptimal Zone Target38 U/mL

Optimal Longevity Zone(21 U/mL)

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

Standard Reference Interval

>10.0 U/mL

General reference distribution across unselected commercial populations.

Optimal Longevity Target

>14.0 U/mL

Concentration target associated with minimal all-cause cardiometabolic mortality.

Technical Reference & Deep Dive

Biochemistry & Enzymatic Pathways

Longevity Risk Architecture & Epidemiology

Deficiency drives histamine intolerance syndrome, presenting with postprandial flushing, headaches, and palpitations.

Pre-Analytical Caveats & Diagnostic Workup

Pre-Analytical Considerations:

Reflexive Testing Protocol:

Confirmatory testing and secondary biomarker panel evaluation for DAO
Targeted imaging or functional organ assessment related to histamine degradation capacity
Comprehensive metabolic and inflammatory baseline panel (CMP, CBC, hs-CRP)

Clinical Citations & Primary Literature (2)

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

Standard vs. Optimal Reference RangesU/mL

Molecular Mechanism & Clinical Purpose

Differential Diagnosis

Elevated Levels (DAO High)

Low Levels (DAO Low)

Technical Reference & Deep Dive

Pre-Analytical Considerations:

Reflexive Testing Protocol:

Associated Longevity Guides & Clinical Calculators

Related Immunology & Longevity Clocks Biomarkers

Standard vs. Optimal Reference RangesU/mL

Molecular Mechanism & Clinical Purpose

Differential Diagnosis

Elevated Levels (DAO High)

Low Levels (DAO Low)

Technical Reference & Deep Dive

Pre-Analytical Considerations:

Reflexive Testing Protocol:

Associated Longevity Guides & Clinical Calculators

Related Immunology & Longevity Clocks Biomarkers