Quest Diagnostics Inc. We offer convenient access to high quality testing and services throughout the United States . We have laboratories in or near all major cities, and esoteric testing laboratories on both coasts, providing a broad range of services to our customers. Convenient specimen collection options include in-office phlebotomy and courier services and more than 2,000 conveniently located patient service centers across the country. We also have a growing international presence, including laboratory operations in the United Kingdom, México, Puerto Rico, and India. Our businesses also offer services and administrative offices in many other countries.