June 26, 2007

Jefferies HealthcareConference

Patients Growth People

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»Safe Harbor Disclaimer

The statements in this presentation which are not historical

facts or information are forward-looking statements. These

forward-looking statements involve risks and uncertainties that

could cause the outcome to be materially different. Certain of

these risks and uncertainties are described in the Quest

Diagnostics Incorporated SEC filings, including our latest Form

10-K. Additional risks may arise from unanticipated events.

A copy of this presentation is available on our website at www.questdiagnostics.com

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»Who is Quest Diagnostics?

Leader in Providing Healthcare Insights and SolutionsComprehensive Diagnostic Testing

Routine ——» Esoteric• Diagnose• Monitor• Predict• Prevent

Advanced Information Technology SolutionsImprove Care and Efficiency

Facilitate Introduction of New TherapeuticsClinical Trials Testing

Touching the Lives of Patients >150 Million Times in 2006

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»Quest Diagnostics: The Leader

Source: Washington G-2 Reports and company estimatesQuest Diagnostics data is proforma for AmeriPath acquisition

US Diagnostic Testing Market: ~$45 B

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»A Leader Across All Product Lines

$ in millions

Based on 2006 Actual Results, proforma for AmeriPath acquisition

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»Favorable Industry Trends

Growing and Aging Population

Innovations in Science & Medicine

Personal Interest in Health

Convergence of Technologies• Genetic Predisposition• Diagnostic Testing• Diagnostic Imaging • Information Technology

Essential Healthcare Service

Influences >70% of Healthcare Decisions

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»Why Quest Diagnostics?

Superior Patient Experience

Six Sigma Quality

Unparalleled Access and Distribution

Innovative Science & Medicine

Advanced Information Technology

Unique Value Proposition

Sustainable Advantage

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IOPs

PSCs

RRLsMain Labs∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃∃

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Patient Service Centersand Laboratory Network

~2,300 Laboratories and Patient Service Centers Serving Half of US Physicians

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>100,000 Physician Users and Growing by >1,000 Physicians Each Month

Electronic Connectivity: Care360 Network

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»Preferred by Physicians

Asked If Physicians Had a Preference Between 2 Largest Labs:

Majority Had a Preference

Overwhelmingly Chose Quest

Recent Nationwide Survey Completed by National Analysts Worldwide

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»Health Plan Contracting Approach

Customize Solutions for Each Health Plan

Offer Differentiated Service and Convenient Access for Their Members

Price Competitively

Focused on Maintaining Mutually Beneficial Relationships

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Approach to DrivingProfitable Growth

Provide Differentiated Service at Competitive PricesFocus on High Growth Segments

Cancer DiagnosticsCardiovascular DiseaseInfectious DiseaseMolecular Diagnostics

Introduce Important & Unique Tests & ServicesExpand Geographic Scope

Expand Diagnostic Scope – Near Patient Testing

Increasing Loyalty with Patients, Physicians and Payers

Building a Sustainable Competitive Advantage

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»AmeriPath Acquisition

Creates Leader in Cancer Diagnostics with 900 MDs and PhDs

AmeriPath has National Scale with Significant Local Presence

• Approximately 400 Pathologists and Clinical Scientists

• Over 200 Hospital Contracts in 22 States

• Approximately 40 Outpatient Facilities in 19 States

Strengthens Leadership in Hospital and Esoteric Testing

Strengthens Relationship with Physicians and Payers

Accelerates Revenue and Earnings Growth

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»Financial Considerations

Enhances Long-term Shareholder Value and EPS Growth

Leverage AmeriPath Brands and Pathologist Relationships

Accelerate Overall Growth Through Cross-selling Clinical and AP Services

Realize Economies of Scale on Esoteric Testing Business

$2 Billion Total Transaction Value with Multiple of ~10x 2008 EBITDA

Driven primarily by growth opportunities

Cost synergies focused at Specialty Laboratories

Rationalize capacity, logistics rationalization, improve purchasing capabilities, eliminate duplicate corporate costs

Maintained Investment Grade Ratings

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»Near Patient Testing

Attractive benefits for hospitals and physician offices

Enables more timely and effective decisions

Expanding product menu

Combine with central lab results to createcomplete patienttesting record available tophysicians and plans

An Opportunity to Improve Patient Care and …

…to Reduce Medical Costs

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Improving Revenue Mix to Higher Margin, Differentiated Services

Quest Diagnostics 2006A Revenue

Gene-based and Esoteric16%

Anatomic Pathology10%

Routine62%

Drugs of Abuse4%

Other8%

AmeriPath 2006A Revenue

Esoteric20%

Anatomic Pathology78%

Other2%

Total Quest Revenue: $6.3 Billion

Total AmeriPath Revenue: $752 million

Pro Forma Quest Diagnostics Revenue

Gene-based and Esoteric17%

Anatomic Pathology17%

Routine56%

Drugs of Abuse3%

Other7%

Total Pro Forma Revenue: ~$7.0 Billion

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»Building on Strength

Industry Leader in a Vital and Growing Industry

−Leadership in All Major Segments

Unique Value Proposition

A Proven Track Record of Integrating Acquisitions

Proven Management Team

Strong Cash Generator

A History of Disciplined Growth

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