Quest Diagnostics Incorporated (DGX)

Quest Diagnostics (DGX) stock has experienced several notable events in the past six months. On October 27, 2025, the company announced a new study demonstrating the high accuracy of its two AD-Detect blood tests for Alzheimer's disease diagnosis. On October 21, 2025, DGX stock declined by 3.1% following the release of its third-quarter financial results, despite a 13.1% increase in third-quarter revenues from 2024. On July 22, 2025, Quest Diagnostics raised its 2025 profit and revenue forecasts, leading to a more than 3% increase in its shares in premarket trading. On April 9, 2025, Quest Diagnostics launched a new laboratory blood test designed to help physicians confirm amyloid brain pathology in patients with mild cognitive impairment or dementia. As of October 20, 2025, DGX was trading near its 52-week high of $190.58, with a 52-week range spanning from $147.37 to $190.58.

Demand for Quest Diagnostics' products and services can exhibit seasonality, influenced by various factors. Demand for routine diagnostic tests tends to increase as people return to the healthcare system for regular check-ups. The prevalence of seasonal illnesses directly impacts the demand for diagnostic testing. Some laboratory test values can vary considerably throughout the year, with significant seasonal fluctuations observed in tests like glucose, white blood cell counts, and vitamin D levels. Quest Diagnostics actively runs special promotions and discounts during seasonal events, which can influence consumer-initiated demand.

Quest Diagnostics, Inc. is a leading provider of diagnostic information services in the Healthcare sector, specifically within the Diagnostics & Research industry. The company offers a comprehensive suite of diagnostic testing, information, and services to a diverse clientele, including physicians, hospitals, patients, consumers, health plans, government agencies, employers, and pharmaceutical companies. Its major products and services encompass routine and advanced clinical testing, anatomic pathology testing, molecular and genomic diagnostics, substance abuse testing, risk assessment services, healthcare information technology solutions, and specific tests for conditions such as Alzheimer's disease, cancer, cardiovascular disease, infectious disease, and neurological disorders.

Quest Diagnostics has a broad geographic presence, with its headquarters in the U.S. and operations in India, Ireland, and Mexico. Its products and services are utilized by customers in over 130 countries across six continents. In the United States, Quest Diagnostics maintains an extensive network, including a national network of laboratories in most major metropolitan areas and approximately 2,000 patient service centers. As of September 26, 2025, there were 5,876 Quest Diagnostics clinics in the United States, with Texas, California, and Florida having the highest number of locations.

In the past year, Quest Diagnostics has maintained a generally positive brand reputation, largely driven by its advancements in diagnostic testing and strategic collaborations. The launch of the two-biomarker AD-Detect panel in April 2025 and the announcement of a new study in October 2025 confirming the high accuracy of these blood tests for Alzheimer's disease diagnosis have significantly bolstered its image. Quest Diagnostics has engaged in collaborations, such as the agreement with Corewell Health to establish a lab services joint venture in Michigan, and a collaboration with Guardant Health to broaden access to Guardant's Shield™ blood-based screening test in the United States. Quest Diagnostics continues to be recognized as a leading provider of diagnostic information services.

Quest Diagnostics (DGX) has a widely held ownership structure, with a mix of institutional, retail, and individual investors. Institutional investors hold a significant portion of the company's stock, with figures ranging from approximately 60.85% to 96.17% across different reports. Major institutional owners include Vanguard Group Inc., BlackRock, Inc., Price T Rowe Associates Inc /md/, State Street Corp, JPMorgan Chase & Co, Boston Partners, Geode Capital Management, Llc, and Victory Capital Management Inc. Individual investors hold a relatively smaller portion, with some sources indicating around 0.43% for insiders and 27.62% to 38.72% for public companies and individual/retail investors.