David Williams founded the GI Lab in 1985 at the University of Florida, when he introduced the assay of serum trypsin-like immunoreactivity (TLI) in the dog to the United States. Over the next two decades students and staff working in the GI Laboratories at Kansas State, Purdue, and most recently Texas A&M Universities established several other novel tests for gastrointestinal diseases for use by veterinarians internationally. His research has been focused on the development and application of new tests for gastrointestinal diseases, particularly those affecting the pancreas, small intestine, stomach and liver of dogs and cats.
He received his veterinary degree from the University of Cambridge and his PhD from the University of Liverpool (where he first developed the canine TLI assay). He was an intern and resident at the University of Pennsylvania, and has held Faculty positions at the University of Florida, Kansas State University, Purdue University, Texas A&M University, and the University of Illinois, where he is presently Head of the Department of Veterinary Clinical Medicine. He continues to work as a consultant and collaborator with the GI Lab, and shares responsibility with Dr Steiner for telephone consultations regarding management of patients diagnosed using the GI Lab services.