As a leading provider of diagnostic testing, Quest Diagnostics serves almost 145 million patients annually. Quest Diagnostics customers include a variety of healthcare specialists including patients, physicians, hospitals, health insurers, employers and government agencies.

Shiel is one of the country's oldest, continuously operating clinical laboratories, and New York City's largest privately held labs servicing Private Physicians, Group Practices, Union and Industrial accounts, Long-Term Care Facilities, and Home Care agencies in the Five Boroughs of NYC, Nassau, Suffolk, Westchester, and Rockland Counties, and Northern and Central New Jersey.