CPT Code 31231: Nasal Endoscopy, Diagnostic, Unilateral or Bilateral

Documentation requirements

Accurate billing for CPT 31231 relies on comprehensive documentation that clearly outlines the scope and medical necessity of the diagnostic nasal endoscopy. The following key elements are essential:

• Note symptoms such as chronic sinonasal symptoms, nasal polyps, facial pain suggestive of sinusitis, or smell disorders.
• Describe the use of a nasal endoscope (rigid or flexible) and whether it was done unilateral or bilateral.
• Include any observed sinonasal pathology, nasal neoplasms, or cerebrospinal fluid leak.
• Specify areas visualized, such as the nasal cavity, sinus passages, or nasal passages.
• Indicate if done for initial diagnosis, interval response, or to guide medical or surgical therapy.
• Document the use of a rigid endoscope or flexible tube.
• Link the exam to the patient's diagnosis and need for accurate diagnosis or treatment planning.

This separate procedure must be clinically justified and well-supported by the medical record to ensure proper medicare reimbursement and CPT code compliance.

Billing guidelines

CPT 31231 covers a diagnostic nasal endoscopy, either unilateral or bilateral, used to directly visualize the nasal cavity, nasal passages, and sinus passages for conditions like nasal polyps, sinonasal neoplasms, or chronic sinonasal symptoms.

Here are the key billing guidelines:

• Report per session: Whether one or both sides are examined, CPT code 31231 is billed once per encounter, not per side. It includes a diagnostic unilateral or bilateral examination.
• Note: Most payers recognize CPT 31231 as inherently covering both unilateral and bilateral procedures, so modifier -50 (bilateral procedure) is usually not required. However, some payers may have specific requirements, so always check the payer’s guidelines before submitting claims.
• Use as a separate procedure: While typically a separate procedure, it may be bundled when performed with balloon dilation, endoscopic sinus surgery, or other major nasal procedures. Use Modifier -59 or -XS to indicate distinct services when appropriate.
• Do not confuse with anterior rhinoscopy: This nasal endoscopy uses a nasal endoscope (rigid or flexible tube) for deeper evaluation, unlike anterior rhinoscopy, which only examines the front of the nasal cavity.
• Medical necessity required: Must be linked to a qualifying diagnosis such as facial pain suggestive of sinusitis, smell disorders, or suspected cerebrospinal fluid leak.
• Proper documentation: Support the service with clear notes on the procedure performed, findings from direct visualization, and relevance to medical or surgical therapy.
• Reimbursement: Coverage may vary by payer. Medicare reimbursement generally requires that services be clinically indicated and part of initial diagnosis, interval surveillance, or pre-operative planning.

Correct use of CPT 31231 ensures accurate payment for services that help identify sinonasal pathology and guide appropriate medical care.