All Quest Diagnostics Locations - Illinois
- Alton
- Arlington Heights
- Aurora
- Barrington
- Bartonville
- Beardstown
- Belleville
- Belvidere
- Bethalto
- Bloomingdale
- Bloomington
- Bolingbrook
- Bourbonnais
- Buffalo Grove
- Cahokia
- Carol Stream
- Champaign
- Chicago
- Collinsville
- Crystal Lake
- Danville
- Decatur
- Dixon
- Elgin
- Elmhurst
- Evanston
- Fairview Heights
- Flossmoor
- Geneva
- Glen Carbon
- Glenview
- Granite City
- Gurnee
- Herrin
- Highland
- Hinsdale
- Hoffman Estates
- Huntley
- Itasca
- Jacksonville
- Joliet
- Lake Bluff
- Lake Zurich
- Lansing
- Lindenhurst
- Lombard
- Maryville
- Mchenry
- Mokena
- Mount Vernon
- Naperville
- Niles
- Norridge
- North Aurora
- Oak Lawn
- Oak Park
- Olympia Fields
- Orland Park
- Palatine
- Palos Heights
- Park Ridge
- Peoria
- Plainfield
- Rockford
- Schaumburg
- Skokie
- Springfield
- St Charles
- Staunton
- Sycamore
- Vernon Hills
- Waterloo
- Watseka
- Westmont
- Wheaton
- Wood Dale
- Woodridge
- Yorkville