UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 8-K

CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF

THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of Earliest Event Reported): March 19, 2025

Quest Diagnostics Incorporated

(Exact Name of Registrant as Specified in Its Charter)

Delaware

(State or other jurisdiction of incorporation)

001-12215		16-1387862
(Commission File Number)		(I.R.S. Employer Identification No.)

500 Plaza Drive
Secaucus, NJ		07094
(Address of principal executive offices)		(Zip Code)

			(973) 520-2700
(Registrant's telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common Stock, $0.01 Par Value	DGX	New York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 7.01. Regulation FD Disclosure

On March 19, 2025, Quest Diagnostics Incorporated (the “Company”) hosted an Investor Day during which members of the leadership team discussed the Company's strategies to drive sustainable growth and deliver long-term shareholder value.

A copy of the presentation materials that were used by members of the Company’s leadership team are furnished as Exhibits 99.1, 99.2, 99.3 and 99.4 to this Current Report on Form 8-K and are incorporated into this Item 7.01 of this Current Report on Form 8-K by reference. The Investor Day presentation materials include information regarding the matters discussed by the Company at Investor Day.

The information in the preceding paragraphs, as well as Exhibits 99.1, 99.2, 99.3 and 99.4, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section. It may only be incorporated by reference into another filing under the Exchange Act or the Securities Act of 1933, as amended, if such subsequent filing specifically references this Current Report on Form 8-K.

The statements in the Investor Day presentation materials which are not historical facts may be forward-looking statements. Readers are cautioned not to place undue reliance on forward-looking statements, which speak only as of the date that they are made and which reflect management's current estimates, projections, expectations or beliefs and which involve risks and uncertainties that could cause actual results and outcomes to be materially different. Risks and uncertainties that may affect the future results of the company include, but are not limited to, adverse results from pending or future government investigations, lawsuits or private actions, the competitive environment, the complexity of billing, reimbursement and revenue recognition for clinical laboratory testing, changes in government regulations, changing relationships with customers, payers, suppliers or strategic partners, acquisitions and other factors discussed in the Company's most recently filed Annual Report on Form 10-K and in any of the Company's subsequently filed Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, including those discussed in the "Business," "Risk Factors," "Cautionary Factors that May Affect Future Results" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" sections of those reports.

Item 9.01. Financial Statements and Exhibits

d.	Exhibit

	99.1	Investor Day Presentation (Davis)
	99.2	Investor Day Presentation (Kuppusamy)
	99.3	Investor Day Presentation (Doherty)
	99.4	Investor Day Presentation (Samad)
	104	The cover page from this current report on Form 8-K, formatted in Inline XBRL.

Signature

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

March 19, 2025

QUEST DIAGNOSTICS INCORPORATED

By:	/s/ Sean D. Mersten
	Sean D. Mersten
	Vice President and Corporate Secretary

Investor Day 2025 Quest Diagnostics

Driving Sustainable Growth, Delivering Long-term Value Jim Davis Chairman, CEO, and President Investor Day 2025 Quest Diagnostics

Safe harbor disclosure The statements in this presentation which are not historical facts may be forward-looking statements. Readers are cautioned not to place undue reliance on forward-looking statements, which speak only as of the date that they are made and which reflect management's current estimates, projections, expectations or beliefs and which involve risks and uncertainties that could cause actual results and outcomes to be materially different. Risks and uncertainties that may affect the future results of the company include, but are not limited to, adverse results from pending or future government investigations, lawsuits or private actions, the competitive environment, the complexity of billing, reimbursement and revenue recognition for clinical laboratory testing, changes in government regulations, changing relationships with customers, payers, suppliers or strategic partners, acquisitions and other factors discussed in the company's most recently filed Annual Report on Form 10-K and in any of the company's subsequently filed Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, including those discussed in the "Business," "Risk Factors," "Cautionary Factors that May Affect Future Results," and "Management's Discussion and Analysis of Financial Condition and Results of Operations" sections of those reports. In the following presentation, references to adjusted EPS refer to adjusted diluted EPS. Any references to operating margin(s) refer to adjusted operating income as a percentage of net revenues. Any references to free cash flow refer to cash flow from operations less capital expenditures. Adjusted EPS, operating margin and free cash flow are non-GAAP financial measures. Please see the explanation of these non-GAAP measures, including the comparable GAAP measure, at the end this presentation and on Investor Relations page on our website. 3 Investor Day 2025 Quest Diagnostics

Key highlights The clinical lab market is expected to remain strong driven by health trends and diagnostic innovation We have a proven strategy to generate above average growth in key channels We expect our investments in advanced diagnostics to deliver double-digit revenue growth across 5 key clinical areas Our operational strategy is designed to improve quality, customer experiences, and productivity Long-term outlook beyond 2025: 4% - 5% revenue CAGR and 7% - 9% adjusted EPS CAGR 4 Investor Day 2025 Quest Diagnostics

Why we exist Purpose The Quest Way Strategy Culture How we grow How we work Purpose Why we exist Working together to create a healthier world, one life at a time Strategy How we grow We help people make the best decisions to improve health by providing high-quality and affordable diagnostic testing insights and services using our scale and extensive reach Culture How we work The 5Cs Customer first Care Collaboration Continuous improvement Curiosity 5 Investor Day 2025 Quest Diagnostics

Quest is a leading provider of diagnostic information services 50% US hospitals and physicians served annually 1/3 US adults served annually ~217M requisitions in 2024 ~8K patient access sites ~5K vehicles >90% of insured lives in the US >80B patient data points >55K employees ~850 MDs/PhDs ~1,600 patents/patents pending Global including in Canada through LifeLabs® 6 Investor Day 2025 Quest Diagnostics

Quest is well positioned in the nearly $90 billion US lab market Physician Channel $58B 2024 Total US Lab Market $89B Hospital Channel $31B POL 11% Quest 12% Other Independent Labs 42% Hospital Outreach 35% Physician 65% Hospital 35% Quest 6% Other Ind Labs 14% Other Hospital 80% 2%-4% CAGR 1%-3% CAGR 1%-2% CAGR POL: physician office laboratory. 7 Investor Day 2025 Quest Diagnostics

We are well positioned for growth in Canada's lab market 2024 Total Canadian Lab Market ~$5B Hospital/Public Health 79% Community Labs 8% LifeLabs 13% ~3% CAGR LifeLabs British Columbia Ontario Saskatchewan 41M people Leading provider of clinical laboratory testing in Canada Headquartered in Toronto 5 primary labs and 350 collection centers Strong growth opportunities in Canada Broadening access to lab services, including advanced diagnostics Expanding into new provinces Increasing consumer interest 8 Investor Day 2025 Quest Diagnostics

Nearly 90% of our revenues come from physicians and hospitals ~$9.9B 2024 revenues +6.7% growth year-over-year Other 12% Hospitals 20% Physicians 68% By Customer Channel Patients 12% Canadian Government 2% Medicaid/Managed Medicaid 8% Medicare/Medicare Advantage 16% Commercial Health Plans 27% Client Bill 35% By Payer 13% administered by Health Plans 9 Investor Day 2025 Quest Diagnostics

Macro trends continue to shape healthcare and favor Quest Demographic shifts-older, sicker population Innovations in lab diagnostics Greater adoption of AI and automation Consumer focus on prevention and wellness 10 Investor Day 2025 Quest Diagnostics

The US population is growing older and sicker Demographic shifts-older, sicker population 74% of adults live with excess weight or obesity 40% of children live with excess weight of obesity 52% of adults have prediabetes or type 2 diabetes 30% of teens have prediabetes 79% increase in early-onset cancers 1 in 2 people with get cancer in their lifetime 2%-12% annual increase in autoimmune diseases Triple the rate of dementia and Alzheimer's disease since 2013 Triple the rate of infant and maternal mortality despite spending the most Decline in life expectancy driven by COVID-19, suicide, and liver and heart disease 11 Investor Day 2025 Quest Diagnotics

The evolution in diagnostics is shaped by "power in the blood" Innovations in lab diagnostics Technological advances are enabling a transition to clinical lab testing 12 Investor Day 2025 Quest Diagnostics

Automation and AI are improving quality and productivity Greater adoption of AI and automation Microbiology Cytology Parasitology Pathology 13 Investor Day 2025 Quest Diagnostics

Consumers are taking charge of their healthcare Consumer focus on prevention and wellness 54% of individuals say holistic care options involving diet, exercise, and counseling are either very or somewhat important to them 65% of individuals say it is important that they be able to monitor their health with apps, wearable devices, etc. 75% of individuals would like healthcare providers to remind them about routine testing and preventive care 2 of 3 consumers have become more concerned about their health "We are entering a new era of medicine… called bio-observability… the ability to observe your own biology through technologies like wearables, continuous monitors, and direct to consumer (DTC) lab testing." - Dr. Casey Means "Good Energy" Fountain Life Function InsideTracker 14 Investor Day 2025 Quest Diagnostics

Our strategy supports above market growth in key channels Physicians Hospitals Expand in high-growth areas 4% - 5% CAGR 5% - 6% CAGR >20% CAGR Capitalize on expanded health plan network access Extend geographic reach Become a partner of choice for large enterprise customers Serve hospitals through scaled reference testing Provide Collaborative Lab Solutions (formerly Professional Lab Services) Expand in new geographies through outreach acquisitions Drive growth in consumer-initiated testing Support life sciences partners with testing and services Deliver insights through data analytics Lead in advanced diagnostics through science and innovation Deliver a better customer experience and productivity improvements through technology Long-term outlook beyond 2025: 4% - 5% revenue CAGR and 7% - 9% adjusted EPS CAGR 16 Investor Day 2025 Quest Diagnostics

Our unique strengths will enable us to capitalize on physician market trends 1 Scale 2 Broad access (PSCs, IOPs) 3 Clinical innovation 4 Health plan access 5 Value PSCs: patient service centers; IOPs: in-office phlebotomists. 17 Investor Dat 2025 Quest Diagnostics

We are leveraging our health plan access to increase our presence in new geographies Physicians Over 1 million net new lives added Segmentation of top 50 MSAs >90% of insured lives in the US Expanding access with new health plan relationships Growth potential Low High Low High Quest brand presence 14 MSAs 20 MSAs 12 MSAs 4 MSAs Focus on faster growing MSAs with high access and low Quest capture MSAs: metropolitan statistical areas. 18 Quest Diagnostics

We continue to expand our focus beyond independent physicians to include enterprise accounts Physicians Physician employment trends Executives/Influencers 35% 17% 48% 2020 31% 20% 49% 2021 26% 22% 52% 2022 25% 22%53% 2023 22% 23% 55% 2024 Independent -11% CAGR Corporate entity +8% CAGR Health System +3% CAGR Summit Health City MD Oak St. Health minute clinic Optum Function C-Suite, executive leaders, influencers of lab decisions Representing finance, medical, operations, analytics, etc. What do they care about? Improved efficiency and patient access Patient and physician satisfaction and engagement Improved quality scores Connectivity, integration and national scale Population health and data Quest's enterprise commercial team is well positioned to partner with large physician groups seeking scaled solutions Source: PAI Physician Employment Study April 2024 19 Investor Day Quest Diagnostics

Hospitals continue to face headwinds and value scaled providers Hospitals Wage and supply inflation Workforce shortages Cost of capital 20 Investor Day Quest Diagnostics

We have a diverse, collaborative approach for helping hospitals improve quality, efficiency, and access to capital Hospitals Reference testing Comprehensive menu across continuum of care Reduces the need for hospitals to invest in advanced technologies Over $1B in revenues today Collaborative Lab Solutions (CoLab) Professional lab management and related services based on expertise and scale Broader than Professional Lab Services ~800M in revenues today Outreach/JVs Access to capital to invest in core assets Continued access to diagnostics innovation Enhanced affordability Note: CoLab previously known as Professional Lab Services. 21 Investor Day 2025 Quest Diagnostics

Our collaborative partnerships with hospitals are the largest opportunity to deliver above market growth in the hospital channel Hospitals Collaborative Lab Solutions (CoLab) Strong growth in CoLab revenue Lab management Workforce Supply chain Analytics Blood collection ~300M 2019 +22% CAGR $800M 2024 >$1B Beyond 2025 Note: CoLab previously known as Professional Lab Services. 22 Investor Day 2025 Quest Diagnostics

We are positioned to deliver strong double-digit growth in key high-growth areas Expan in high-growth areas Consumer ~$100M in revenue (Direct sales + channel partners) Questhealth.com consumer-initiated testing Partnerships Menu expansion Life Sciences ~$90M in revenue Phase I - IV decentralized clinical trials Companion diagnostics and assay development In vitro diagnostic studies Analytics ~$40M in revenue Cross channel Direct sales Integrators These channels are expected to deliver >20% combined CAGR 23 Investor Day 2025 Quest Diagnostics

We expect new and existing advanced diagnostic tests in 5key clinical areas to deliver double-digit growth Advanced Diagnostics Oncology Advanced Cardiometabolic Health Women's and Reproductive Health Brain Health Autoimmune Disorders Haystack MRDTM IsoPSA STEP500 liquid and tissue ApoB Lipoprotein(a) Insulin resistance panel with score QNatalR Advanced (NIPS) QHeritR carrier screening AD-DetectTM Alzheimer's disease blood testing New liquid biomarkers ANAlyzeRTM primary care screening Therapy guidance (RA, IBD) Portfolio of new and existing advanced diagnostic tests generated ~900 million in 2024 24 Investor Day 2025 Quest Diagnostics

We are focused on maximizing value from recent acquisitions Completed 8 acquisitions in 2024 which are expected to generate ~$1 billion in annualized revenue Regional independent labs Health system outreach labs Capability-building assets Lenco Diagnostic Laboratory Greater New York region February 2024 Steward Massachusetts February 2024 PathAI Diagnostics Tennessee June 2024 Digital pathology LifeLabs Canda August 2024 Alina Health MN, western WI September 2024 NY Physicians New York September 2024 OhioHealth Ohio October 2024 University Hospitals Ohio December 2024 25 Investor Day 2025 Quest Diagnostics

We continue to see robust opportunities for hospital outreach acquisitions Physician Channel $58B POL 11% Quest 12% Other Independent Labs 42% Hospital Outreach 35% Hospital outreach labs comprise ~$20B of the physician channel 600+ health systems ~20 deals completed by Quest in the last decade 26 Investor Day 2025 Quest Diagnostics

We are also building strategic growth partnerships Fresenius Medical Care Provides end-stage renal disease (ESRD) dialysis testing for over 2,600 dialysis centers in the US serving more than 200K patients Building dialysis-related water testing capabilities Leverage Quest's national network to enable near-access services Daytime testing optimizes lab utilization Benefits: Faster results for some dialysis-related testing for patients, greater value for Fresenius Medical Care, and improved access to the dialysis market for Quest 27 Investor Day 2025 Quest Diagnostics

Engaged people, lean processes and technology investments improve quality, productivity, and the customer experience 3% annual productivity and cost savings target through Invigorate Superior customer experience and cost excellence People Customer-centric and highly-engaged employees driving performance and innovation Enterprise Operations Process Lean, standardized, and digital processes powering experience and productivity Technology Automation, AI, and new software tools enabling operational excellence Across order to cash 28 Investor Day 2025 Quest Diagnostics

We are transforming our order-to-cash process through Project Nova IT initiative will modernize underlying applications to improve customer experiences and lower IT costs Onboard Order Collect Transport Test Result Bill Service EHRs Quanum® EHRs IDAA Quanum® Ortec QDTRac QSuite LIS AP/Derm LIS Esoteric/Genetic LIS EHRs MyQuest QBS Salesforce Project Nova Modernize systems Improve customer experiences Lower IT spend Improve productivity 29 Investor Day 2025 Quest Diagnostics

Key takeaways The clinical lab market is expected to remain strong driven by health trends and diagnostic innovation We have a proven strategy to generate above average growth in key channels We expect our investments in advanced diagnostics to deliver double-digit revenue growth across 5 key clinical areas Our operational strategy is designed to improve quality, customer experiences, and productivity Long-term outlook beyond 2025: 4% - 5% revenue CAGR and 7% - 9% adjusted EPS CAGR 30 Investor Day 2025 Quest Diagnostics

Note on Non-GAAP Financial Measures As used in this presentation the term "reported" refers to measures under accounting principles generally accepted in the United States ("GAAP"). The term "adjusted" refers to non-GAAP operating performance measures that exclude special items such as restructuring and integration charges, amortization expense, gains and losses on investments, and excess tax benefits ("ETB") associated with stock-based compensation. The company has provided discussion of projected operating margin, which is adjusted operating income as a percentage of net revenues, and a compound annual growth rate projection beyond 2025 of 7%-9% for adjusted diluted earnings per share ("EPS"), which are non-GAAP measures. The company is unable to present a reconciliation of adjusted operating income as a percentage of net revenues to operating income as a percentage of net revenues and adjusted diluted EPS to reported diluted EPS, the most comparable GAAP measure due to the inherent uncertainty and variability in the nature and amount of special items referenced above, and the amount of these items could be significant in any of the associated periods. The company has provided a compound annual growth rate projection beyond 2025 of 7%-9% for adjusted diluted earnings per share ("EPS"), which is a non-GAAP measure. The company is unable to present a reconciliation of adjusted diluted EPS to reported diluted EPS, the most comparable GAAP measure due to the inherent uncertainty and variability in the nature and amount of special items referenced above, and the amount of these items could be significant in any of the associated periods. Non-GAAP adjusted measures are presented because management believes those measures are useful adjuncts to GAAP results. Non-GAAP adjusted measures should not be considered as an alternative to the corresponding measures determined under GAAP. Management may use these non-GAAP measures to evaluate our performance period over period and relative to competitors, to analyze the underlying trends in our business, to establish operational budgets and forecasts and for incentive compensation purposes. We believe that these non-GAAP measures are useful to investors and analysts to evaluate our performance period over period and relative to competitors, as well as to analyze the underlying trends in our business and to assess our performance. 31 Investor Day 2025 Quest Diagnostics

Karthik Kuppusamy, PhD Senior Vice President, Clinical Solutions Diagnostic Innovation as a Growth Driver Investor Day 2025 Quest Diagnostics

2 INVESTOR DAY 2025 Quest Diagnostics Safe harbor disclosure The statements in this presentation which are not historical facts may be forward-looking statements. Readers are cautioned not to place undue reliance on forward-looking statements, which speak only as of the date that they are made and which reflect management's current estimates, projections, expectations or beliefs and which involve risks and uncertainties that could cause actual results and outcomes to be materially different. Risks and uncertainties that may affect the future results of the company include, but are not limited to, adverse results from pending or future government investigations, lawsuits or private actions, the competitive environment, the complexity of billing, reimbursement and revenue recognition for clinical laboratory testing, changes in government regulations, changing relationships with customers, payers, suppliers or strategic partners, acquisitions and other factors discussed in the company's most recently filed Annual Report on Form 10-K and in any of the company's subsequently filed Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, including those discussed in the "Business," "Risk Factors," "Cautionary Factors that May Affect Future Results," and "Management's Discussion and Analysis of Financial Condition and Results of Operations" sections of those reports.

2 INVESTOR DAY 2025 Quest Diagnostics Key highlights We expect to deliver double-digit revenue growth in advanced diagnostics across 5 key clinical areas We are well positioned to grow revenues for Haystack MRD, building on our leadership in oncology We are committed to delivering the most comprehensive portfolio of diagnostic lab innovation By empowering earlier diagnosis and prevention, we are improving clinical and economic outcomes

3 INVESTOR DAY 2025 Quest Diagnostics We deliver diagnostic innovation across the continuum of care to offer comprehensive, scaled solutions Risk evaluation Periodic screening Disease diagnosis Therapy selection Therapy monitoring Follow-up care What is my risk of getting a disease? Is it possible I have a disease? Am I sure I have a disease? What therapy is best for me? Is my therapy working? Is my success sustainable? Disease prognosis What direction will the disease take?

4 INVESTOR DAY 2025 Quest Diagnostics Oncology Advanced Cardiometabolic Health Women's and Reproductive Health Brain Health Autoimmune Disorders We expect new and existing advanced diagnostic tests in 5 key clinical areas to deliver double-digit growth Haystack MRD IsoPSA STEP500 liquid and tissue QNatal Advanced (NIPS) QHerit carrier screening AD-Detect Alzheimer's disease blood testing New liquid biomarkers ANAlyzeR primary care screening Therapy guidance (RA, IBD) In these 5 areas, advanced diagnostic tests generated ~$900 million in 2024 ApoB Lipoprotein(a) Insulin Resistance Panel with Score Advanced Diagnostics

5 INVESTOR DAY 2025 Quest Diagnostics We develop our own lab innovations and partner/buy to source others Leverage IVD suppliers' innovation ELF Liver Fibrosis Assessment Quest AD-Detect P-Tau 217, 181 1 Develop organic innovations via Quest RandD Quest AD-Detect 42/40 Amyloid Beta OmegaCheck Cardiovascular Risk 2 License and create innovation from third-party IP QNatal Advanced Prenatal Genetics Ion Mobility 3 Partnerships that leverage our scale IsoPSA GRAIL's Galleri MCED test 4 Acquire new capabilities to extend portfolio Haystack MRD PathAI Diagnostics digital pathology 5 ELF - Enhanced Liver Fibrosis. Siemens Healthineers HAYSTACKMRD By Quest Diagnostics

Diagnostic innovation as a growth driver Yuri Fesko, MD, Senior Vice President and Chief Medical Officer Dan Edelstein, Vice President and General Manager, Haystack MRD Mouris Saghir, PhD, Vice President and General Manager, Cardiometabolic, Endocrine, and Wellness Kathleen Valentine, Vice President and General Manager, Women's and Reproductive Health and Core Neurology Panel discussion Investor Day 2025 Quest Diagnostics

Our advanced cardiometabolic solutions focus on prevention via early identification ~128M Americans have heart disease ~38M have type 2 diabetes 36M have chronic kidney disease (CKD) 1 in 3 Americans have metabolic-associated steatotic liver disease (MASLD) Only 7% of the population has normal metabolic health Quest approach and testing solutions HbA1c Insulin Resistance with Score FIB-4 Enhanced Liver Fibrosis Kidney profile Cystatin C ApoB Lp(a) MPO Primary aldosterone Testosterone Diabetes Heart disease Endocrine disorders MASLD CKD Insulin Resistance Panel with Score Predicts diabetes before HbA1c Apolipoprotein B Identifies risk that lipid panels miss Myeloperoxidase (MPO) Identifies dangerous inflammation 7 INVESTOR DAY 2025 Quest Diagnostics

With 18+ million patients treated for cancer in the US, our sensitive MRD test will optimize patient management with early detection Surgery Adjuvant therapy Additional therapy "Is adjuvant therapy successful?" Whole-exome sequencing + personalized test build Treatment response assessment Residual disease testing Recurrence surveillance Analytical validation results show that the Haystack MRD testis extremely sensitive with an LoD95 of 0.0006% tumor fraction "Is the cancer coming back?" "Did we surgically remove all the cancer?" HAYSTACK MRD Tumor burden 8 INVESTOR DAY 2025 Quest Diagnostics

9 INVESTOR DAY 2025 Quest Diagnostics Delivering differentiated solutions across each stage of a woman's life Fertility testing and comprehensive trimester-based testing QHerit carrier screening QNatal noninvasive prenatal screening STIs: chlamydia, gonorrhea, trichomonas, syphilis Pelvic inflammatory disease and vaginitis STIs/vaginitis self-collect option at 2,000 PSCs Cervical cancer - Hologic Genius Digital Cytology System Sexually transmitted infections (STIs) Routine, guideline-based screenings during well-woman visits Pregnancy/reproductive health for every step of the reproductive journey Symptomatic solutions to help diagnose and treat

Quest AD-Detect blood testing helps assess risk of Alzheimer's disease in early stages 12% - 18% of people age 60 or older are living with mild cognitive impairment... a possible sign of Alzheimer's disease New AD-Detect panel combines amyloid beta and P-tau217 Normal Abnormal Cognitively normal Mild cognitive impairment Dementia Clinical disease stage Biomarker levels Amyloid beta P-Tau Brain changes Memory Function PET Scan AD-Detect Study found 91% sensitivity 91% specificity medRxiv CSH Cold Spring Harbor BMJ Yale THE PREPRINT SERVER FOR HEALTH SCIENCES Development and clinical validation of blood-based multibiomarker models for the evaluation of brain amyloid pathology Darren M Weber, Matthew A Stroh, Steven W Taylor, Robert J Lagier, Judy Z Louie, Nigel J Clarke, David E Vaillancourt, Sruti Rayaprolu, ID Ranjan Duara, Michael K Racke doi: https://doi.org/10.1101/2025.02.27.25322892 10 INVESTOR DAY 2025 Quest Diagnostics

11 INVESTOR DAY 2025 Quest Diagnostics We help providers personalize diagnosis, treatment, and care for their patients with autoimmune disorders Features ANAlyzeR Autoimmune Screening Unmet need: early diagnosis Screening/diagnosis Personalized medicine for most effective treatment selection Unmet need: treatment optimization Therapy selection Serological testing to monitor disease activity Unmet need: maintain remission Disease monitoring ~24M Americans 100+ different types 4 - 5 years on average for diagnosis Autoimmune disease

12 INVESTOR DAY 2025 Quest Diagnostics Haystack MRD leverages Quest's unique strengths and scale to broaden access National connectivity Interfaces with >1,000 EMRs in the US Now adding Epic Aura oncology (Q3) Epic $1B annual oncology revenues Blood testing at scale ~8,000 patient access sites for blood draws Streamlined access to biopsy tissue 400+ pathologists ~10k tissue specimens/day Comprehensiveness of care Treatment selection (STEP500+)

We are challenging the existing hypothesis of cardiovascular disease >400k Normal lipid levels are cardioprotective Low LDL Low triglyceride High HDL Existing hypothesis Normal lipid levels + Functioning HDL are cardioprotective Emerging science However Measure the functioning ability of HDL to carry cholesterol to the liver HDL Assay to measure HDL function Cardiovascular mortality trends* 320 340 360 380 400 420 440 460 480 500 100 105 110 115 120 125 130 135 2000 2005 2010 2015 2020 Cardiovascular mortality (in Thousands) Avg LDL-C (mg/dL) LDL-C levels Cardiovascular Mortality of heart attack patients have normal lipid levels * Tsao CW, et al. 2023. doi:10.1161/CIR.0000000000001123 13 INVESTOR DAY 2025 Quest Diagnostics

Developing novel solutions for preeclampsia Potentially life-threatening hypertensive disorder during pregnancy ~16% of pregnant women in the US are affected by hypertensive disorder of pregnancy Half of hypertensive women develop preeclampsia during pregnancy ~5.5M pregnancies in US each year Diagnosis Acute increase in blood pressure AND Proteinuria OR Thrombocytopenia Impaired renal function Impaired liver function Pulmonary edema Current challenges Lack of accuracy Lab solutions specific to hospital settings No well-established method to predict severity Limited options for early Identification 14 INVESTOR DAY 2025 Quest Diagnostics

15 INVESTOR DAY 2025 Quest Diagnostics We are empowering earlier diagnosis and prevention We are delivering diagnostic lab services that address unmet clinical needs affecting large patient populations We are driving innovation to deliver earlier, more precise health insights-empowering clinicians with confidence to act sooner Through our expertise and scale, we make lab testing easier to access and more affordable for patients and providers

16 INVESTOR DAY 2025 Quest Diagnostics Key takeaways We expect to deliver double-digit revenue growth in advanced diagnostics across 5key clinical areas We are well positioned to grow revenues for Haystack MRD, building on our leadership in oncology We are committed to delivering the most comprehensive portfolio of diagnostic lab innovation By empowering earlier diagnosis and prevention, we are improving clinical and economic outcomes

Improving Quality, Experiences, and Productivity Cathy Doherty Executive Vice President, Regional Businesses Alex Louis Senior Vice President, Enterprise Operations Investor Day 2025 Quest Diagnostics

3 INVESTOR DAY 2025 Quest Diagnostics Key highlights Our operational strategy is focused on improving quality, customer and employee experiences, and productivity We see ample runway to continue to generate 3% in annual cost savings and productivity through Invigorate We will realize productivity improvements across our entire order-to-cash process by Standardizing, simplifying, and digitizing our processes Optimizing quality and productivity with AI and automation Attracting and retaining engaged, customer-centric employees

4 INVESTOR DAY 2025 Quest Diagnostics 3% annual productivity and cost savings target through Invigorate People Customer-centric and highly-engaged employees driving performance and innovation Technology Automation, AI, and new software tools enabling operational excellence Process Lean, standardized, and digital processes powering experience and productivity Enterprise operations Talented people, lean processes, and technology investments improve quality, productivity, and the customer experience SUPERIOR CUSTOMER EXPERIENCE AND COST EXCELLENCE ACROSS ORDER TO CASH

5 INVESTOR DAY 2025 Quest Diagnostics We are making improvements across our order-to-cash value stream People Customer-centric and highly engaged employees driving performance and innovation Process Lean, standardized, and digital processes powering experience and productivity Technology Automation, AI, and new software tools enabling operational excellence Onboard Order Collect Test Result Bill Service $ Transport

6 INVESTOR DAY 2025 Quest Diagnostics We are driving productivity across the order-to-cash value stream... 5% 14% 5% 11% 3% 8% 45% 12% All productivity improvements compared to 2022 performance, except eBills delivered, which is compared to 2023 performance; reqs per day per FTE excludes COVID Patients served per FTE per day Non-productive stops Requisitions per day per FTE Calls per 100 requisitions Accounts set up within 3 days Electronic order rate MyQuest result views eBills delivered Onboard Order Collect Test Result Bill Service $ Transport

7 INVESTOR DAY 2025 Quest Diagnostics …while improving customer experiences Customer Satisfaction Score CSAT Net Promoter Score NPS Patients 89% 74 Physicians 86% 57 Key customer experience metrics Onboard Order Collect Test Result Bill Service $ Transport

8 INVESTOR DAY 2025 Quest Diagnostics We are simplifying the patient journey through digitization Digitizing customer interaction to keep patients informed and prepared before their visit Reducing administrative tasks in the PSC, enabling employees to focus on service Streamlining patient access to results and engaging them through the process Pre-visit Visit Post-visit Collect Result MyQuest A Andrew Results In progress A A

9 INVESTOR DAY 2025 Quest Diagnostics We are transforming our logistics with AI Transport Route Optimization (Details and Automation) Dynamic routing capabilities to increase on-road efficiencies Enhanced visibility into on-road operations with real-time driver positioning and mapping Real-time operational insights including live lab arrival profiles Advanced voice recognition software that digitally interacts with clients to schedule routine pickups Reduces client wait times, improving client experience Increases capacity for staff to take higher priority requests, increasing efficiency Routing capabilities Voice recognition

10 INVESTOR DAY 2025 Quest Diagnostics We are improving our billing process through digitization Bill $ Quest Welcome to Quest's billing services Leveraging machine learning to better understand insurance denial data Lnking transaction data (claim and claim response) to enable enhanced identification of trends and shifts in patterns of denials and reimbursements Trends now identified in days instead of weeks, informing our upfront editing and trailering processes Improved, mobile-friendly digital billing experience that seamlessly integrates into MyQuest Simplified bill lookup, shopping-cart experience, and convenient 1-time verification process Digital billing Machine learning

11 INVESTOR DAY 2025 Quest Diagnostics Service = 100% = 12.2M 100% = 13.2M 2023 2024 Phone Email Chat 71% 18% 11% 75% 19% 6% We are improving client service through technology We have a multi-channel, digital-first, customer service strategy that leverages AI 5.5 2022 2024 Calls/100 reqs Contact center interactions 5.5 6.0

12 INVESTOR DAY 2025 Quest Diagnostics We are driving quality, flexibility, and productivity in all our labs through our touchless, trackless lab vision Test Automated 3 labs Automation throughout the lab Front end Sorting, accessioning Analytical process Instrument loading, testing Storage and retrieval Transportation Using innovation and unique solutions Modular automated solutions Partnering with automation vendors to deploy lab-specific solutions Clifton Lenexa Marlborough

13 INVESTOR DAY 2025 Quest Diagnostics Test Our automated accessioning station will dramatically speed up specimen management 3X Increase in departmental productivity

14 INVESTOR DAY 2025 Quest Diagnostics Test Cobots can supplement labor for highly repetitive and transport tasks 2X Efficiency in samples handling

15 INVESTOR DAY 2025 Quest Diagnostics Test QuantiFERON pre-analytical automation eliminates the manual labeling and racking of tubes needed to perform TB testing ~90% reduction in human touches ~2.5X processing speed

16 INVESTOR DAY 2025 Quest Diagnostics Test Hologic Genius Digital Cytology implementation will improve productivity, medical quality, and ease the risk of cytotechnologist staffing shortages >40% Improvement in resource productivity Genius 57001579999028 Gyn Approximate Cell Count: 75600 Algorithm Version 1.0.12.0

17 INVESTOR DAY 2025 Quest Diagnostics Modernize systems | Improve customer experiences | Lower IT spend | Improve productivity Project Nova We are transforming our order-to-cash process through Project Nova EMRs Ortec QBS EMRs Quanum Salesforce MyQuest QSuite LIS Esoteric/Genetic LIS AP/Derm LIS EMRs IT initiative will modernize underlying applications to improve customer experiences and lower IT costs IDAA QDTRac Onboard Order Collect Test Result Bill Service $ Transport Quanum

18 INVESTOR DAY 2025 Quest Diagnostics We are investing in our people and our culture... Targeted retention programs Targeted wage adjustments Making every job better and easier Customer-first training programs Highly engaged employees who are empowered to problem solve every day

19 INVESTOR DAY 2025 Quest Diagnostics ...and see results in engagement scores and reduced attrition ~15% ~24% ~21% ~18% YE '19 YE '22 YE '23 YE '24 >5 percentage point improvement in 2 years Frontline voluntary turnover We have a highly engaged workforce And we are reducing attrition Employee engagement score above industry average Employee Engagement Score Healthcare benchmark 73 75

20 INVESTOR DAY 2025 Quest Diagnostics Key takeaways Our operational strategy is focused on improving quality, customer experience, and productivity We see ample runway to continue to generate 3% in annual cost savings and productivity through Invigorate We will realize productivity improvements across our entire order-to-cash process by Standardizing, simplifying, and digitizing our processes Optimizing quality and productivity with AI and automation Attracting and retaining engaged, customer-centric employees

Sam Samad Executive Vice President and Chief Financial Officer Long-term Financial Outlook Investor Day 2025 Quest Diagnostics

2 INVESTOR DAY 2025 Quest Diagnostics Safe harbor disclosure The statements in this press release which are not historical facts may be forward-looking statements. Readers are cautioned not to place undue reliance on forward-looking statements, which speak only as of the date that they are made and which reflect management's current estimates, projections, expectations or beliefs and which involve risks and uncertainties that could cause actual results and outcomes to be materially different. Risks and uncertainties that may affect the future results of the company include, but are not limited to, adverse results from pending or future government investigations, lawsuits or private actions, the competitive environment, the complexity of billing, reimbursement and revenue recognition for clinical laboratory testing, changes in government regulations, changing relationships with customers, payers, suppliers or strategic partners, acquisitions and other factors discussed in the company's most recently filed Annual Report on Form 10-K and in any of the company's subsequently filed Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, including those discussed in the "Business," "Risk Factors," "Cautionary Factors that May Affect Future Results," and "Management's Discussion and Analysis of Financial Condition and Results of Operations" sections of those reports. In the following presentations, references to adjusted EPS refer to adjusted diluted EPS. Any references to operating margin(s) refer to adjusted operating income as a percentage of net revenues. Any references to free cash flow refer to cash flow from operations less capital expenditures. Adjusted EPS, operating margin and free cash flow are non-GAAP financial measures. Please see the explanation of these non-GAAP measures, including the comparable GAAP measure, at the end this presentation and on Investor Relations page on our website.

3 INVESTOR DAY 2025 Quest Diagnostics Key highlights We have a consistent track record of generating profitable growth over the long term We have balanced capital deployment priorities with an expectation to return the majority of FCF to shareholders We expect to drive operating margin expansion beyond 2024 through revenue growth and our operational strategy Long-term outlook beyond 2025: 4% - 5% revenue CAGR and 7% - 9% adjusted EPS CAGR Long-term outlook contemplates investments in Project Nova to modernize our entire order-to-cash process

4 INVESTOR DAY 2025 Quest Diagnostics We have had a consistent track record of generating profitable growth over the long term Over the last 5years we delivered a ~5% revenue CAGR and ~6% adjusted EPS CAGR $7,726 $9,872 2019 2024 $6.56 $8.93 2019 2024 ~6% CAGR $ Millions Revenues Adjusted EPS ~5% CAGR

5 INVESTOR DAY 2025 Quest Diagnostics We delivered a solid TSR through a volatile period We outperformed the SandP 500 healthcare index over the last several years 80.3% 75.3% DGX SandP 500 Healthcare 5-year TSR 40.1% 20.5% DGX SandP 500 Healthcare 3-year TSR 40.6% 3.8% DGX SandP 500 Healthcare 1-year TSR 2nd quartile performance 2nd decile performance 1st decile performance *Note: TSRs through 2/28/25.

6 INVESTOR DAY 2025 Quest Diagnostics We are well positioned to accelerate revenue and earnings growth Recap of full year 2025 guidance and assumptions 2025 Revenue Guidance 2025 Adjusted EPS Guidance 2025 Guidance Assumptions $10.70B - $10.85B +8.4% to +9.9% y-o-y ~3% organic revenue growth Haystack MRD expected to be slightly less dilutive versus the prior year $30M of investment to fund Project Nova and comply with FDA regulations of LDTs Operating margin to expand versus the prior year Net interest expense to be ~$275M Tax rate is approximately 25% ~114M diluted shares outstanding $10.78B Midpoint +9.1% y-o-y $9.55 - $9.80 $9.68 Midpoint +8.3% y-o-y

7 INVESTOR DAY 2025 Quest Diagnostics We have had a balanced approach to capital deployment over the last 10 years 2015-2024: Investing in our business while returning capital to shareholders Note: Cash generated from operations and divestitures not equal to cash deployed, as sources of cash do not include increase in debt over this period. Invested ~$15.4B Returned to shareholders ~$3.6B Capex ~$4.9B MandA ~$2.8B Dividends ~$6.3B Share repurchases Cash generated from operations and divestitures ~$9.1B ~$8.5B ~$17.6B Dividend increased every year since 2011 with a 16% CAGR

8 INVESTOR DAY 2025 Quest Diagnostics Proven track record of returning the majority of FCF to shareholders $704 $823 $923 $817 $843 $1,587 $1,830 $1,314 $864 $909 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 62% 99% 77% 72% FCF ($ millions) 76% 39% 137% 130% 68% 53% We have returned the majority of FCF to shareholders nearly every year over the last 10 years FCF: free cash flow. % of FCF returned to shareholders

9 INVESTOR DAY 2025 Quest Diagnostics We will maintain a disciplined capital deployment strategy $1.5B - $1.7B capital expenditures (~4.5% of revenue) $4.5B - $5.0B operating cash flow $3.0B - $3.3B free cash flow Expected capital deployment 2025-2027 ~$1.0B dividends ~$1.5B acquisitions ~$0.7B share repurchases Steady annual growth Drives 1%-2% revenue growth Offset option dilution Majority of FCF to shareholders

10 INVESTOR DAY 2025 Quest Diagnostics We target MandA in 3 key strategic areas Regional independent labs Capability-building assets Health system outreach labs Completed 8 acquisitions in 2024 Targeted financial criteria Accretive to adj EPS in year 1 Accretive to ROIC (at least 10%) by year 3 NY Physicians ENCO DIAGNOSTIC LABORATORY LifeLabs AllinaHealth OhioHealth University Hospitals Steward PathAI Diagnostics

11 INVESTOR DAY 2025 Quest Diagnostics Project Nova: Multi-year investment to modernize our entire order-to-cash process Unlocks a variety of streamlined benefits including: Improvements to the customer, employee, and patient experiences Operational improvements Reduced technology-related operating costs Accelerated revenue opportunities Benefits start to ramp up in 2027 Total project related costs (2025-2031): $250M - $310M ~60% capital expenditures ~40% operating costs Completion timeline: by 2032 Long-term outlook contemplates investments in Project Nova

12 INVESTOR DAY 2025 Quest Diagnostics Our long-term outlook beyond 2025 assumes steady revenue and earnings growth Total revenues 4% - 5% CAGR Includes 1% - 2% growth from new acquisitions Operating margins +75 to +150 basis points by the end of 2027 Adjusted EPS* 7% - 9% CAGR Free cash flow Free cash flow growth commensurate with earnings growth Adjusted EPS growth plus our dividend yield expected to deliver a high single-digit to low double-digit CAGR

13 INVESTOR DAY 2025 Quest Diagnostics Long-term outlook assumptions beyond 2025 Includes 1% - 2% growth from new acquisitions ~25% tax rate 3% Invigorate savings and productivity enables 40%+ contribution margin on organic growth Potential return of PAMA cuts captured in the low end of outlook Reflects investments in Project Nova ~114M shares outstanding Free cash flow growth commensurate with earnings growth Leverage: 2.5x - 3.0x gross debt to EBITDA

14 INVESTOR DAY 2025 Quest Diagnostics Key takeaways We have a consistent track record of generating profitable growth over the long term We have balanced capital deployment priorities with an expectation to return the majority of FCF to shareholders We expect to drive operating margin expansion beyond 2024 through revenue growth and our operational strategy Long-term outlook beyond 2025: 4% - 5% revenue CAGR and 7% - 9% adjusted EPS CAGR Long-term outlook contemplates investments in Project Nova to modernize our entire order-to-cash process

15 INVESTOR DAY 2025 Quest Diagnostics Note on Non-GAAP Financial Measures As used in this press release the term "reported" refers to measures under accounting principles generally accepted in the United States ("GAAP"). The term "adjusted" refers to non-GAAP operating performance measures that exclude special items such as restructuring and integration charges, amortization expense, gains and losses on investments, and excess tax benefits ("ETB") associated with stock-based compensation. The company has provided discussion of projected operating margin, which is an adjusted operating income as a percentage of net revenues, and a compound annual growth rate projection beyond 2025 of 7%-9% for adjusted diluted earnings per share ("EPS"), which are non-GAAP measures. The company is unable to present a reconciliation of adjusted operating income as a percentage of net revenues to operating income as a percentage of net revenues and adjusted diluted EPS to reported diluted EPS, the most comparable GAAP measure due to the inherent uncertainty and variability in the nature and amount of special items referenced above, and the amount of these items could be significant in any of the associated periods. The company has provided a compound annual growth rate projection beyond 2025 of 7%-9% for adjusted diluted earnings per share ("EPS"), which is a non-GAAP measure. The company is unable to present a reconciliation of adjusted diluted EPS to reported diluted EPS, the most comparable GAAP measure due to the inherent uncertainty and variability in the nature and amount of special items referenced above, and the amount of these items could be significant in any of the associated periods. Non-GAAP adjusted measures are presented because management believes those measures are useful adjuncts to GAAP results. Non-GAAP adjusted measures should not be considered as an alternative to the corresponding measures determined under GAAP. Management may use these non-GAAP measures to evaluate our performance period over period and relative to competitors, to analyze the underlying trends in our business, to establish operational budgets and forecasts and for incentive compensation purposes. We believe that these non-GAAP measures are useful to investors and analysts to evaluate our performance period over period and relative to competitors, as well as to analyze the underlying trends in our business and to assess our performance.

16 INVESTOR DAY 2025 Quest Diagnostics Adjusted diluted EPS from continuing operations The following table reconciles adjusted diluted earnings per share from continuing operations ("Diluted EPS") to reported results under GAAP. 2019 2024 Low High Diluted EPS - as reported $6.13 $7.69 $8.34 $8.59 Amortization of intangible assets (a) 0.61 0.84 1.05 1.05 Restructuring and integration charges (b) 0.42 0.42 0.11 0.11 Other (c) (0.50) (0.04) 0.13 0.13 Gains and losses on investments (d) 0.00 0.10 0.00 0.00 Excess tax benefits associated with stock-based compensation (0.10) (0.08) (0.08) (0.08) Diluted EPS - as adjusted $6.56 $8.93 $9.55 $9.80 Twelve months ended December 31, 2025 Twelve months ended December 31,

17 INVESTOR DAY 2025 Quest Diagnostics Adjusted diluted EPS from continuing operations (a) Income tax impacts were primarily calculated using combined statutory tax rates of 25.5%. (b) Represents costs primarily associated with workforce reductions, systems conversions and integration incurred in connection with further restructuring and integrating our business. Income tax impacts were primarily calculated using combined statutory tax rates of 25.5%. (c) For the 12 months ended December 31, 2025, represents estimated pre-tax net losses of $15 million, principally associated with the increase in the fair value of the contingent consideration accrual associated with previous acquisitions. No income tax benefits are recorded on the losses associated with the contingent consideration accrual. For the 12 months ended December 31, 2024, includes pre-tax (gains)/losses associated with the change in the fair value of the contingent consideration accrual associated with previous acquisition and a non-recurring $8 million pre-tax gain associated with a foreign exchange forward contract utilized in conjunction with an acquisition. No income tax benefits are recorded on the losses associated with the contingent consideration accrual. For the 12 months ended December 31, 2019, primarily represents a gain associated with the sale and leaseback of a property, a gain associated with the decrease in the fair value of the contingent consideration accruals associated with previous acquisitions, and a gain associated with an insurance claim for hurricane related losses, partially offset by costs incurred related to a data security incident and non-cash asset impairment charges. Income tax impacts were primarily calculated using combined statutory tax rates of 25.5%. For the gain associated with an insurance claim for hurricane related losses in 2019, there was no net income tax expense as we were able to utilize net operating loss carryforwards for which a valuation allowance had previously been established. For the gain in 2019 associated with the decrease in the fair value of the contingent consideration accruals associated with previous acquisitions, there was no net income tax expense related to acquisitions for which the gain was non-taxable. (d) Primarily represents gains and losses associated with changes in the carrying value of our strategic investments. Income tax impacts were primarily calculated using combined statutory tax rates of 25.5%.

Free cash flow The following table reconciles free cash flow to reported results under GAAP (dollars in millions). Net cash provided by operating activities Less: capital expenditures Free cash flow Twelve months ended December 31, 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025-2027 $ 967 $ 1,116 $ 1,175 $ 1,200 $ 1,243 $ 2,233 $ 1,718 $ 1,272 $ 1,334 $4,500 - $5,000 (263) (293) (252) (383) (400) (418) (403) (404) (408) (425) 1,500 - 1,700 $ 704 $ 823 $ 923 $ 817 $ 843 $ 1,587 $ 1,830 $ 1,314 $ 864 $ 909 $3,000 - $3,300 18 INVESTOR DAY 2025 Quest Diagnostics