|Traded as||NYSE: DGX|
|Founded||New York City, USA (1967)|
|Headquarters||Madison, New Jersey, USA|
|Area served||USA, Mexico, UK, India|
|Key people||Steve Rusckowski (CEO)|
|Revenue||US$10.4 Billion (2010)|
|Operating income||US$8.5 Billion (2010)|
|Total equity||US$4 Billion (2010)|
Quest Diagnostics Incorporated is a corporation based in the United States that provides clinical laboratory services, it runs operations in United Kingdom, Mexico, Brazil, Puerto Rico and a laboratory in India and also has collaborative agreements internationally with various hospitals and clinics. It is a member of the Fortune 500 and the S&P 500, with corporate headquarters located in Madison, New Jersey. The company has approximately 43,000 employees. The company has over $7.5 billion dollars in revenue and offers access to diagnostic testing services for cancer, cardiovascular disease, infectious disease and neurological disorders.
The company has been listed on Fortune Magazine’s "World’s Most Admired Companies" since 2008. In addition, the company has been named listed on the Dow Jones Sustainability World Index and North America Index and is consistently recognized as among the nation’s healthiest employers. The company’s products have been recognized by the Edison Institute for Leadership in Diagnostic Innovation. The company’s "Quest Diagnostics Health Trends" reports identify and track trends in disease and wellness, they are made available as a public service to inform patients, health professionals and policy-makers about the current status of the nation's health. The Quest Diagnostics Drug Testing Index, published twice each year, is a comprehensive source of information on workplace drug use 
Quest Diagnostics set a record in April 2009 when it paid $302 million to the government to settle a Medicare fraud case alleging the company sold faulty medical testing kits. It was the largest qui tam (whistleblower) settlement paid by a medical lab for manufacturing and distributing a faulty product. In May 2011, Quest paid $241 million to the state of California to settle a False Claims Act case that alleged the company had overcharged Medi-Cal, the state’s medical aid program for low-income individuals, and provided illegal kickbacks as incentives for healthcare providers to use Quest labs.
- 1967: Founded by Paul A. Brown, MD as Metropolitan Pathology Laboratory, Inc., in New York.
- 1969: Name Changed to MetPath, Inc., in Teaneck, New Jersey.
- 1982: MetPath was acquired by what was then known as Corning Glass Works, and subsequently renamed Corning Clinical Laboratories.
- 1997: Quest Diagnostics becomes an independent company as a spin-off from Corning. Kenneth Freeman appointed CEO.
- 1997: Acquires clinical laboratory division of Branford, CT-based Diagnostic Medical Laboratory, Inc. (DML).
- 1999: Acquires SmithKline Beecham Clinical Laboratories; GlaxoSmithKline still holds a large portion of Quest Diagnostics stock. The SmithKline Beecham acquisition includes a joint venture ownership with CompuNet Clinical Laboratory
- 2000: Launch of Six Sigma program leading the charge to raise the quality of healthcare delivery in the United States.
- 2001: Completes acquisition of Ohio-based MedPlus, Inc. (NASDAQ: MEDP), a healthcare technology company.
- 2002: Completes acquisition of Virginia-based American Medical Laboratories, Inc. (AML) and an affiliated company of AML, LabPortal, Inc., for approximately $500 million in cash.
- 2003: Completes acquisition of California-based Unilab Corporation (NASDAQ: ULAB) in a transaction valued at approximately $800 million .
- 2005: Completes acquisition of Kansas-based LabOne, Inc. (NASDAQ: LABS) for approximately $934 million.
- 2006: Completes acquisition of Virginia-based Focus Diagnostics, Inc., an infectious and immunologic disease laboratory, for approximately $185 million in cash.
- 2007: Quest Diagnostics celebrates its 10th year after being spun off from Corning.
- 2007: Completes acquisition of Sweden-based Hemocue, a point-of-care diagnostic testing company.
- 2007: Acquires AmeriPath (and subsidiary Specialty Laboratories) from Welsh, Carson, Anderson & Stowe, becoming the leading provider of cancer diagnostic testing services.
- 2011: Acquires Athena Diagnostics from Thermo Fisher Scientific
- 2011: Completes acquisition of Celera Corporation, a company that became famous by its sequencing of the Human Genome.
- 2012: Names former Philips Healthcare CEO Stephen Rusckowski as CEO.
- 2012: Quest Diagnostics bought all the labs including the business from UMASS Memorial Hospitals in Worcester, MA. 
- "International Facilities & Operations". Quest Diagnostics. Retrieved 2012-02-15.
- "Birla Sun Life Insurance Names Quest Diagnostics its Exclusive Provider of Health Assessment Services in India". Quest Diagnostics. 2007-03-31. Retrieved 2012-02-15.
- "Our Growing International Presence". Quest Diagnostics. Retrieved 2012-02-15.
- "Quest Diagnostics Ranked Among FORTUNE Magazine's 'World's Most Admired Companies' For Third Consecutive... - MADISON, N.J., March 5 /PRNewswire-FirstCall/". New Jersey: Prnewswire.com. Retrieved 2012-02-15.
- "World's Most Admired Companies - Industries - 2010 - Health Care: Pharmacy and Other Services". Fortune. March 22, 2010. Retrieved 2012-02-16.
- Quest Diagnostics (2011-10-06). "Quest Diagnostics Selected as Member of Dow Jones® Sustainability Index | CSR News". justmeans.com. Retrieved 2012-02-15.
- "Quest Diagnostics Honored for Diagnostic Innovation at 2011 Edison Awards - Apr 6, 2011". Questdiagnostics.mediaroom.com. 2011-04-06. Retrieved 2012-02-15.
- Smith, Hubble (Oct. 15, 2011 | 2:02 a.m.). "Quest Diagnostics named best place to work - Business - ReviewJournal.com". Las Vegas Review-Journal. Retrieved 2012-02-16. "Quest Diagnostics was named best place to work in Southern Nevada among companies with 5,000 or more employees, the Southern Nevada Human Resources Association announced Friday."
- "Health Trends™ Reports from Quest Diagnostics track disease and wellness benchmarks". Questdiagnostics.com. Retrieved 2012-02-15.
- "Drug Testing Index: Employer Solutions". Quest Diagnostics. Retrieved 2012-02-15.
- Harrison, Sheena (October 23, 2011). "Opioid testing helps curb workers comp claims". Business Insurance, a publication of Crain Communications Inc. Retrieved 2012-02-15. Text "79" ignored (help); Text "342" ignored (help); Text "304" ignored (help); Text "92# " ignored (help)
- "Businessman exposed problems with Quest subsidiary's blood test kits; led to $302 million settlement." Phillips & Cohen LLP press release. April 15, 2009.
- "Attorney General Kamala D. Harris announces $241 million settlement with Quest Diagnostics." State of California Department of Justice. May 19, 2011.
- "Quest Diagnostics Acquires Assets Of Diagnostics Medical Laboratory Inc.". Quest Diagnostics. Retrieved 2012-02-15.
- "Six Sigma Quality?". Quest Diagnostics. Retrieved 2011-10-24.
- Quest Diagnostics Successfully Completes Acquisition of Celera May 17, 2011. Celera Corporation. Retrieved 2012-02-16.