A computed tomography (CT) scan is a diagnostic imaging tool that uses X-rays and computer processing to create cross-sectional images of the body. This technology allows healthcare providers to visualize internal structures with greater detail than conventional X-rays. Because CT scans involve exposure to ionizing radiation, the authority to order these procedures is strictly controlled to ensure patient safety and clinical appropriateness. Ordering is regulated by state laws, institutional policies, and third-party payer requirements.
Licensed Physicians Who Place Orders
Medical Doctors (MDs) and Doctors of Osteopathic Medicine (DOs) represent the core group of professionals with the broadest, most independent authority to order CT scans. Their training and licensure grant them wide latitude to determine the necessity of this diagnostic test across various medical specialties and settings. A physician’s authority is constrained primarily by their scope of practice and the requirement for clinical justification. The order must be supported by a demonstrable medical problem, with the physician intending to use the scan results for patient management.
Ordering Authority of Advanced Practice Providers
Advanced Practice Providers (APPs), such as Nurse Practitioners (NPs) and Physician Assistants (PAs), frequently order CT scans as part of their diagnostic workup. The ability of these providers to order imaging tests is determined by individual state scope-of-practice laws, which vary considerably across the country. In some states, APPs have full practice authority, allowing them to order tests independently, while in other jurisdictions, privileges may depend on a supervisory or collaborative agreement with a physician. Institutional credentialing protocols at hospitals or imaging centers can place further limits on who can authorize a scan.
Clinical Necessity and the Referral Process
Regardless of who signs the order, a CT scan must be supported by clear “clinical necessity,” meaning there must be a valid medical reason for the procedure. This justification is often documented using standardized diagnostic codes, such as ICD-10 codes, which signal the signs or symptoms prompting the test. The ordering provider carries the responsibility for documenting this medical necessity to ensure compliance with regulatory standards. For a patient, obtaining a scan requires a formal referral from the treating provider, which directs the patient to the imaging facility. For non-emergent procedures, this process often involves insurance authorization, known as pre-certification or pre-approval, which confirms medical necessity before coverage is granted.