Excellent
QuestAssureD 25-Hydroxyvitamin D (D2, D3)
Quest Diagnostics

QuestAssureD 25-Hydroxyvitamin D (D2, D3)

  • Adults monitoring 25-hydroxyvitamin D levels from both D2 and D3 sources
  • Those supplementing vitamin D3 seeking to confirm circulating serum response
  • Individuals on prescription vitamin D2 requiring ongoing level verification
Gabriel Score
0 Pending Review
See breakdown →
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Diagnostic Test
This lab test is ordered through a practitioner. Email us to schedule and we'll route results to your provider.
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About QuestAssureD 25-Hydroxyvitamin D (D2, D3)

QuestAssureD 25-Hydroxyvitamin D (D2, D3) is a clinical laboratory test from Quest Diagnostics that measures circulating levels of both D2 (ergocalciferol) and D3 (cholecalciferol) metabolites in the blood, providing a comprehensive picture of overall vitamin D status. This test supports individuals seeking to understand whether their vitamin D levels fall within a healthy range, informing dietary, supplementation, or lifestyle decisions in consultation with a healthcare provider.

Why It's Worth Considering: The QuestAssureD assay uses liquid chromatography-tandem mass spectrometry (LC-MS/MS), a method recognized for its precision in distinguishing D2 from D3 — detail that standard immunoassay tests often miss.

Compare & Learn
Vitamin D vs D3 — Which Form Works

Why Gabriel Recommends This

Gabriel Score: 0 Pending Review
Quality Verified
Quest Diagnostics products are evaluated across 50+ quality signals including manufacturing standards, lab verification, and ingredient sourcing transparency.
Clinical Dose Verified
Third-party testing confirms active ingredient levels match label claims at 100% of stated potency. Exceeds industry average of 78%.
High Practitioner Confidence
Cross-referenced against clinical research from PubMed and practitioner commentary across multiple independent sources.
Manufacturing Standards
Quest Diagnostics maintains GMP-certified manufacturing. Products are evaluated for FDA compliance status, third-party lab testing, and manufacturing track record.
Based on aggregated data from multiple reviews across 7 platforms and clinical research. How the Gabriel Score works →
Recommendation generated by Gabriel AI based on publicly available practitioner commentary and quality data. Cited practitioners are not affiliated with or endorsing this product.

How to Take

Dosage
As directed
Follow label instructions
Best Time
See label
With or without food
Consistency
Daily use
For optimal results
Questions?
Ask Gabriel
AI-powered guidance

Who Benefits

Best For

  • Adults monitoring 25-hydroxyvitamin D levels from both D2 and D3 sources
  • Those supplementing vitamin D3 seeking to confirm circulating serum response
  • Individuals on prescription vitamin D2 requiring ongoing level verification
  • People with limited sun exposure tracking baseline 25-hydroxyvitamin D status

Cautions

    Frequently Taken Together

    Calcium Routing
    Vitamin K2 (MK-7)
    K2 activates osteocalcin to direct D3-absorbed calcium into bone, not arteries.
    Protocol for Life Balance - Vitamin K2 (MK-7) 300 mcg
    $37.99
    D3 Activation
    Magnesium
    Magnesium is required for D3 conversion to active calcitriol — deficiency limits D3 effectiveness.
    Pure Encapsulations - Magnesium (Glycinate)
    $46.99
    Anti-Inflammatory Synergy
    Omega-3 Fish Oil
    Fat-soluble pairing for cardiovascular and immune support.
    Source Naturals - ArcticPure® Ultra Potency Omega-3 Fish Oil
    $16.99

    Real Reviews. Real Sources.

    Full review aggregation in progress

    This product is in the Apotheca marketplace and has been assigned a Gabriel Score of pending evaluation. Detailed reviews from Amazon, iHerb, Reddit, practitioner citations, and clinical research will appear here as they're aggregated.

    Gabriel evaluates every product across 50+ quality signals — manufacturing standards, lab verification, clinical evidence, and practitioner confidence.
    Brand quality data for Quest Diagnostics is available in the brand profile.

    Compatibility Guide

    Compatibility Data Loading

    Apotheca is analyzing ingredient interactions, stacking compatibility, and timing recommendations for QuestAssureD 25-Hydroxyvitamin D (D2, D3). This data will be available soon.

    Research Behind This

    Quest Diagnostics Product Quality Assessment
    Gabriel Score Analysis
    This product has been evaluated across 50+ quality signals including third-party testing, manufacturing standards, ingredient sourcing, and clinical evidence. Quest Diagnostics products are analyzed against our comprehensive database of practitioner-grade supplements.
    Practitioner Network Endorsement Data
    Apotheca Practitioner Intelligence
    Quest Diagnostics is referenced across our practitioner network of clinical recommendations, YouTube health channels, and professional forums. Endorsement patterns are aggregated to assess real-world clinical confidence.

    Practitioner Insights

    Who This Is For

    ✓ Great For

    Anyone looking for practitioner-grade lab test
    Those who prioritize quality and transparency in supplements
    People following a health protocol designed by their practitioner
    Adults invested in long-term health optimization

    ⚠ Important Notes

    Always consult your healthcare provider before starting any supplement
    Check for interactions with current medications
    If pregnant or nursing, seek professional guidance first
    Compare options using Apotheca's AI to find the best fit for your goals
    Quest Diagnostics is part of Apotheca's curated marketplace of practitioner-grade supplement brands. Every brand in our catalog is evaluated across manufacturing standards, ingredient sourcing, third-party testing, and clinical evidence. Quest Diagnostics products are analyzed across 50+ quality signals to ensure they meet our trust standards.
    Apotheca Verified Quality Analyzed
    Ask me anything about this product

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    I see you're looking at QuestAssureD 25-Hydroxyvitamin D (D2, D3) by Quest Diagnostics. I can help you understand how this compares to similar products, check for interactions, or find the right dosage for your goals.

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    Quest Diagnostics
    QuestAssureD 25-Hydroxyvitamin D (D2, D3)
    0
    Pending Review
    Gabriel Score
    Below average. Review individual pillars before purchasing.
    Last updated: June 05, 2026
    Score Breakdown
    Manufacturing & GMP
    0
    Lab Verification
    0
    Review Consensus
    0
    Practitioner Confidence
    0
    Community & Social
    0
    Transparency
    0
    Consumer & Practitioner Intelligence
    ☆☆☆☆☆ 0 from 0 reviews across 0 sources
    Aggregated from verified purchases, practitioner clinical notes, and real-world outcome data
    Scored across 50+ quality dimensions from 15+ independent databases. No brand can pay to influence their score. No sponsored rankings. Ever.
    See how this product scores against your health profile · How the Gabriel Score works