Quest Diagnostics Inc

Quest Diagnostics Inc orporated Delaware 16-1387862 (State of Incorporation) (I.R.S. Employer Identification Number) 500 Plaza Drive Secaucus, NJ 07094 (973) 520-2700

PART I - FINANCIAL INFORMATION Page Item 1. Financial Statements (unaudited) Index to unaudited consolidated financial statements filed as part of this report: Consolidated Statements of Operations for the Three and Nine Months Ended September 30, 2026 and 2025 2

Consolidated Statements of Comprehensive Income for the Three and Nine Months Ended September 30, 2026 and 2025 3

Consolidated Balance Sheets as of September 30, 2026 and December 31, 2025 4

Consolidated Statements of Cash Flows for the Nine Months Ended September 30, 2026 and 2025 5

Consolidated Statements of Stockholders' Equity for the Three and Nine Months Ended September 30, 2026 and 2025 6

Notes to Consolidated Financial Statements (unaudited) 8

Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations

Management's Discussion and Analysis of Financial Condition and Results of Operations 28

Item 3. Quantitative and Qualitative Disclosures About Market Risk

See Item 2. "Management's Discussion and Analysis of Financial Condition and Results of Operations" 40

QUEST DIAGNOSTICS INCORPORATED AND SUBSIDIARIES CONSOLIDATED STATEMENTS OF OPERATIONS FOR THE THREE AND NINE MONTHS ENDED SEPTEMBER 30, 2026 AND 2025 (unaudited) (in millions, except per share data)

Three Months Ended September 30, Nine Months Ended September 30, 2026 2025 2026 2025 Net revenues $ 3,097 $ 2,816 $ 9,035 $ 8,229 Operating costs and expenses and other operating income: Cost of services 2,055 1,867 6,024 5,474 Selling, general and administrative 523 501 1,556 1,463 Amortization of intangible assets 37 39 112 117 Other operating expense, net 3 23 6 5 Total operating costs and expenses, net 2,618 2,430 7,698 7,059 Operating income 479 386 1,337 1,170 Other income (expense): Interest expense, net ( 61 ) ( 66 ) ( 187 ) ( 200 ) Other (expense) income, net ( 2 ) 8 12 18 Total non-operating expense, net ( 63 ) ( 58 ) ( 175 ) ( 182 ) Income before income taxes and equity in earnings of equity method investees 416 328 1,162 988 Income tax expense ( 99 ) ( 77 ) ( 261 ) ( 233 ) Equity in earnings of equity method investees, net of taxes 9 8 23 35

Net income 326 259 924 790 Less: Net income attributable to noncontrolling interests 14 14 40 43 Net income attributable to Quest Diagnostics $ 312 $ 245 $ 884 $ 747

Earnings per share attributable to Quest Diagnostics' common stockholders:

Diluted $ 2.78 $ 2.16 $ 7.86 $ 6.57 Weighted average common shares outstanding: Basic 110 112 110 112 Diluted 112 113 112 113

The accompanying notes are an integral part of these statements.

QUEST DIAGNOSTICS INCORPORATED AND SUBSIDIARIES CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME FOR THE THREE AND NINE MONTHS ENDED SEPTEMBER 30, 2026 AND 2025 (unaudited) (in millions) Three Months Ended September 30, Nine Months Ended September 30, 2026 2025 2026 2025 Net income $ 326 $ 259 $ 924 $ 790 Other comprehensive income (loss): Foreign currency translation adjustment ( 4 ) ( 24 ) ( 39 ) 48

Other comprehensive (loss) income ( 4 ) ( 24 ) ( 39 ) 48 Comprehensive income 322 235 885 838 Less: Comprehensive income attributable to noncontrolling interests 14 14 40 43 Comprehensive income attributable to Quest Diagnostics $ 308 $ 221 $ 845 $ 795

The accompanying notes are an integral part of these statements.

QUEST DIAGNOSTICS INCORPORATED AND SUBSIDIARIES CONSOLIDATED BALANCE SHEETS SEPTEMBER 30, 2026 AND DECEMBER 31, 2025 (unaudited) (in millions, except per share data) September 30, 2026 December 31, 2025 Assets Current assets: Cash and cash equivalents $ 797 $ 420 Accounts receivable, net of allowance for credit losses of $ 27 and $ 25 as of September 30, 2026 and December 31, 2025, respectively 1,712 1,408 Inventories 218 189 Prepaid expenses and other current assets 390 361 Total current assets 3,117 2,378 Property, plant and equipment, net 2,275 2,203 Operating lease right-of-use assets 670 657 Goodwill 9,112 8,945 Intangible assets, net 1,634 1,636 Investments in equity method investees 139 136 Other assets 274 270 Total assets $ 17,221 $ 16,225 Liabilities and Stockholders' Equity Current liabilities: Accounts payable and accrued expenses $ 1,643 $ 1,600 Current portion of long-term debt 10 504 Current portion of long-term operating lease liabilities 181 174 Total current liabilities 1,834 2,278 Long-term debt 5,540 5,167 Long-term operating lease liabilities 554 537 Other liabilities 1,262 957 Commitments and contingencies Redeemable noncontrolling interest 81 80 Stockholders' equity: Quest Diagnostics stockholders' equity: Common stock, par value $ 0.01 per share; 600 shares authorized as of both September 30, 2026 and December 31, 2025; 162 shares issued as of both September 30, 2026 and December 31, 2025 2 2 Additional paid-in capital 2,397 2,381 Retained earnings 10,593 9,994 Accumulated other comprehensive loss ( 66 ) ( 27 ) Treasury stock, at cost; 52 shares as of both September 30, 2026 and December 31, 2025 ( 5,294 ) ( 5,180 ) Total Quest Diagnostics stockholders' equity 7,632 7,170 Noncontrolling interests 318 36 Total stockholders' equity 7,950 7,206 Total liabilities and stockholders' equity $ 17,221 $ 16,225

The accompanying notes are an integral part of these statements.

QUEST DIAGNOSTICS INCORPORATED AND SUBSIDIARIES CONSOLIDATED STATEMENTS OF CASH FLOWS FOR THE NINE MONTHS ENDED SEPTEMBER 30, 2026 AND 2025 (unaudited) (in millions) Nine Months Ended September 30, 2026 2025 Cash flows from operating activities: Net income $ 924 $ 790 Adjustments to reconcile net income to net cash provided by operating activities: Depreciation and amortization 440 425 Provision for credit losses 5 2 Deferred income tax expense 155 118 Stock-based compensation expense 63 63

Other, net 22 37 Changes in operating assets and liabilities: Accounts receivable ( 308 ) ( 153 ) Accounts payable and accrued expenses 244 113 Income taxes payable ( 24 ) ( 1 ) Other assets and liabilities, net ( 35 ) 27 Net cash provided by operating activities 1,486 1,421 Cash flows from investing activities: Business acquisitions, net of cash acquired ( 39 ) ( 51 )

Other investing activities, net 2 ( 20 ) Net cash used in investing activities ( 455 ) ( 440 ) Cash flows from financing activities: Proceeds from borrowings 494 410 Repayments of debt ( 504 ) ( 1,011 ) Purchases of treasury stock ( 252 ) ( 150 ) Exercise of stock options 108 61 Employee payroll tax withholdings on stock issued under stock-based compensation plans ( 40 ) ( 44 ) Dividends paid ( 279 ) ( 263 ) Distributions to noncontrolling interest partners ( 35 ) ( 43 ) Contributions from noncontrolling interest partners 25 - Other financing activities, net ( 169 ) ( 61 ) Net cash used in financing activities ( 652 ) ( 1,101 ) Effect of exchange rate changes on cash and cash equivalents and restricted cash ( 2 ) 3 Net change in cash and cash equivalents and restricted cash 377 ( 117 ) Cash and cash equivalents and restricted cash, beginning of period 420 549 Cash and cash equivalents and restricted cash, end of period $ 797 $ 432

The accompanying notes are an integral part of these statements.

QUEST DIAGNOSTICS INCORPORATED AND SUBSIDIARIES CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY FOR THE THREE AND NINE MONTHS ENDED SEPTEMBER 30, 2026 AND 2025 (unaudited) (in millions)

For the Three Months Ended September 30, 2026 Quest Diagnostics Stockholders' Equity Shares of Common Stock Outstanding Common Stock Additional Paid-In Capital Retained Earnings Accumulated Other Compre- hensive Loss Treasury Stock, at Cost Non- controlling Interests Total Stock- holders' Equity Balance, June 30, 2026 110 $ 2 $ 2,374 $ 10,374 $ ( 62 ) $ ( 5,172 ) $ 303 $ 7,819 Net income 312 11 323 Other comprehensive loss, net of taxes ( 4 ) ( 4 ) Dividends declared ( 93 ) ( 93 ) Distributions to noncontrolling interest partners ( 11 ) ( 11 ) Issuance of common stock under benefit plans 1 7 8 Stock-based compensation expense 20 20 Exercise of stock options 3 22 25 Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans ( 1 ) ( 1 ) ( 2 ) Purchases of treasury stock ( 150 ) ( 150 ) Contributions from noncontrolling interest partners 15 15 Balance, September 30, 2026 110 $ 2 $ 2,397 $ 10,593 $ ( 66 ) $ ( 5,294 ) $ 318 $ 7,950 For the Nine Months Ended September 30, 2026 Quest Diagnostics Stockholders' Equity Shares of Common Stock Outstanding Common Stock Additional Paid-In Capital Retained Earnings Accumulated Other Compre- hensive Loss Treasury Stock, at Cost Non- controlling Interests Total Stock- holders' Equity Balance, December 31, 2025 110 $ 2 $ 2,381 $ 9,994 $ ( 27 ) $ ( 5,180 ) $ 36 $ 7,206 Net income 884 35 919 Other comprehensive loss, net of taxes ( 39 ) ( 39 ) Dividends declared ( 285 ) ( 285 ) Distributions to noncontrolling interest partners ( 31 ) ( 31 ) Issuance of common stock under benefit plans ( 38 ) 60 22 Stock-based compensation expense 63 63 Exercise of stock options 1 12 95 107 Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans ( 21 ) ( 19 ) ( 40 ) Purchases of treasury stock ( 1 ) ( 250 ) ( 250 ) Contributions from noncontrolling interest partners 278 278 Balance, September 30, 2026 110 $ 2 $ 2,397 $ 10,593 $ ( 66 ) $ ( 5,294 ) $ 318 $ 7,950

The accompanying notes are an integral part of these statements.

For the Three Months Ended September 30, 2025 Quest Diagnostics Stockholders' Equity Shares of Common Stock Outstanding Common Stock Additional Paid-In Capital Retained Earnings Accumulated Other Compre- hensive Loss Treasury Stock, at Cost Non- controlling Interests Total Stock- holders' Equity Balance, June 30, 2025 112 $ 2 $ 2,332 $ 9,682 $ ( 16 ) $ ( 4,772 ) $ 37 $ 7,265 Net income 245 12 257 Other comprehensive loss, net of taxes ( 24 ) ( 24 ) Dividends declared ( 90 ) ( 90 ) Distributions to noncontrolling interest partners ( 12 ) ( 12 ) Issuance of common stock under benefit plans 2 6 8 Stock-based compensation expense 20 20 Exercise of stock options 2 21 23 Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans ( 1 ) ( 1 ) ( 2 ) Purchases of treasury stock ( 1 ) ( 150 ) ( 150 ) Balance, September 30, 2025 111 $ 2 $ 2,355 $ 9,837 $ ( 40 ) $ ( 4,896 ) $ 37 $ 7,295 For the Nine Months Ended September 30, 2025 Quest Diagnostics Stockholders' Equity Shares of Common Stock Outstanding Common Stock Additional Paid-In Capital Retained Earnings Accumulated Other Compre- hensive Loss Treasury Stock, at Cost Non- controlling Interests Total Stock- holders' Equity Balance, December 31, 2024 111 $ 2 $ 2,361 $ 9,360 $ ( 88 ) $ ( 4,857 ) $ 35 $ 6,813 Net income 747 37 784 Other comprehensive income, net of taxes 48 48 Dividends declared ( 270 ) ( 270 ) Distributions to noncontrolling interest partners ( 35 ) ( 35 ) Issuance of common stock under benefit plans 1 ( 52 ) 73 21 Stock-based compensation expense 63 63 Exercise of stock options 3 62 65 Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans ( 20 ) ( 24 ) ( 44 ) Purchases of treasury stock ( 1 ) ( 150 ) ( 150 ) Balance, September 30, 2025 111 $ 2 $ 2,355 $ 9,837 $ ( 40 ) $ ( 4,896 ) $ 37 $ 7,295

The accompanying notes are an integral part of these statements.

Table of Contents QUEST DIAGNOSTICS INCORPORATED AND SUBSIDIARIES NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (unaudited) (in millions, unless otherwise indicated)

1. DESCRIPTION OF BUSINESS Background Quest Diagnostics Incorporated and its subsidiaries ("Quest Diagnostics"or the"Company") work across the healthcare ecosystem to create a healthier world, one life at a time. The Company's diagnostic information services ("DIS") business provides diagnostic insights from the results of its laboratory testing to empower people, physicians, and organizations to take action to improve health outcomes. Derived from one of the world's largest databases of de-identifiable clinical lab results, the Company's diagnostic insights reveal new avenues to identify and treat disease, inspire healthy behaviors and improve healthcare management. In the right hands and with the right context, the Company's diagnostic insights can inspire actions that transform lives and create a healthier world. The Company provides services to a broad range of customers within its primary customer channels - physicians (including those associated with accountable care organizations ("ACOs") and Federally Qualified Health Centers ("FQHCs")), hospitals, and patients and consumers. Other customers include health plans, employers, new and emerging retail healthcare providers, government agencies, pharmaceutical companies and other commercial clinical laboratories. The Company offers broad access to clinical testing through a network of laboratories, patient service centers, phlebotomists in physician offices, and connectivity resources, including call centers and mobile phlebotomists, nurses and other health and wellness professionals. The Company's large in-house staff of medical and scientific experts, including medical directors, scientific directors, genetic counselors and board-certified geneticists, provide medical and scientific consultation to healthcare providers and patients regarding the Company's tests and test results, and help them best utilize Quest Diagnostics' services to improve outcomes and enhance satisfaction. The Company's Diagnostic Solutions ("DS") group, which represents the balance of the Company's consolidated net revenues, includes the Company's risk assessment services business, which offers solutions for insurers, and the Company's healthcare information technology businesses, which offer solutions for healthcare providers and payers.

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Presentation The interim unaudited consolidated financial statements reflect all adjustments which in the opinion of management are necessary for a fair statement of results of operations, comprehensive income, financial condition, cash flows and stockholders' equity for the periods presented. Except as otherwise disclosed, all such adjustments are of a normal recurring nature. Operating results for the interim periods are not necessarily indicative of the results that may be expected for the full year. These interim unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements included in the Company's 2025 Annual Report on Form 10-K. The year-end balance sheet data was derived from the audited consolidated financial statements as of December 31, 2025 but does not include all the disclosures required by accounting principles generally accepted in the United States ("GAAP").

The accounting policies of the Company are the same as those set forth in Note 2 to the audited consolidated financial statements contained in the Company's 2025 Annual Report on Form 10-K.

Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

The Company's unvested restricted stock units that contain non-forfeitable rights to dividends are participating securities and, therefore, are included in the earnings allocation in computing earnings per share using the two-class method. Basic earnings per common share is calculated by dividing net income attributable to Quest Diagnostics, adjusted for earnings allocated to participating securities, by the weighted average number of common shares outstanding. Diluted earnings per common share is calculated by dividing net income attributable to Quest Diagnostics, adjusted for earnings allocated to

Table of Contents QUEST DIAGNOSTICS INCORPORATED AND SUBSIDIARIES NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - CONTINUED (unaudited) (in millions, unless otherwise indicated)

participating securities, by the weighted average number of common shares outstanding after giving effect to all potentially dilutive common shares outstanding during the period. Potentially dilutive common shares include the dilutive effect of outstanding stock options and performance share units granted under the Company's Amended and Restated Employee Long-Term Incentive Plan ("ELTIP") and its Amended and Restated Non-Employee Director Long-Term Incentive Plan ("DLTIP"), as well as the dilutive effect of accelerated share repurchase agreements, if applicable. Earnings allocable to participating securities include the portion of dividends declared as well as the portion of undistributed earnings during the period allocable to participating securities.