When a patient requires a diagnostic procedure, which of the following is required?

A written order from the provider is essential when a patient requires a diagnostic procedure because it serves as a formal request for the necessary evaluation or testing. This order ensures that the procedure is medically justified, aligns with the patient's health needs, and adheres to legal standards for patient care. It typically includes important details such as the type of procedure, the reason for it, and any specific instructions that need to be conveyed to the medical facility or technician performing the procedure. This documentation is crucial for both clinical and administrative purposes, including insurance billing and patient record-keeping.

Other options, while relevant in specific contexts, do not fulfill the primary requirement for initiating a diagnostic procedure. A referral form may be necessary if a patient is being directed to a specialist, but it is not mandatory for all diagnostic tests. An insurance request form might be used for pre-authorization for certain tests but does not replace the need for a provider's written order. Similarly, a written letter of release may be applicable in situations like postoperative clearance or when a patient is being discharged but is not a requirement for obtaining a diagnostic test.