This industry comprises establishments known as medical and diagnostic laboratories primarily engaged in providing analytic or diagnostic services, including body fluid analysis and diagnostic imaging, generally to the medical profession or to the patient on referral from a health practitioner. Illustrative Examples: Dental or medical X-ray laboratories Medical pathology laboratories Diagnostic imaging centers Medical testing laboratories Medical forensic laboratories Cross-References. Establishments, such as dental, optical, and orthopedic laboratories, primarily engaged in providing the following activities to the medical profession, respectively: making dentures, artificial teeth, and orthodontic appliances to prescription; grinding of lenses to prescription; and making orthopedic or prosthetic appliances to prescription are classified in Industry 33911, Medical Equipment and Supplies Manufacturing.