CPT 31231: Diagnostic Nasal Endoscopy of Nasal Cavity
CPT code 31231 denotes a diagnostic nasal endoscopy in which an endoscope is introduced into the nasal cavity to inspect internal nasal structures on one or both sides. This procedure is widely used in otolaryngology for visualization of mucosal disease, nasal polyps, and anatomic causes of obstruction. Its reproducible documentation and alignment with clinical guidelines make it a common code for ENT diagnostic workflows nationwide.
Key payers addressed in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Coverage and coding nuances across these payers can affect authorization requirements, allowed settings of service, and documentation expectations for medical necessity.
Readers will find a concise overview of the clinical purpose of the code, the typical sites of service where it is performed, common ICD-10 diagnostic pairings used to support medical necessity, and nearby or related CPT procedures. The publication summarizes common billing modifiers used with nasal endoscopy codes and highlights payer considerations relevant to claims processing and audit risk. This briefing is intended to inform billing managers, coding specialists, and clinical leaders about how CPT code 31231 is applied in practice and what documentation and coding context typically accompany its use.
Sign up for cpt 31231 policy alerts
Get alerted when payer policies referencing 31231 are released or updated.
Billing Code Overview
CPT code 31231 describes a diagnostic nasal endoscopy in which an endoscope is inserted into the nasal cavity to examine the internal nasal structures on one or both sides. This procedure is a diagnostic endoscopic evaluation of the nasal cavity performed to visualize mucosa, assess for obstruction, polyps, inflammation, or other anatomic abnormalities.
Service type: Diagnostic nasal endoscopy
Typical site of service: Office, outpatient clinic, or ambulatory surgical center
Clinical & Coding Specifications
Clinical Context
A 42-year-old patient presents to an Otolaryngology clinic with a 6-month history of nasal congestion, intermittent purulent rhinorrhea, facial pressure, and decreased sense of smell. Prior medical therapy including intranasal corticosteroids and oral antibiotics provided incomplete relief. The provider schedules an in-office diagnostic nasal endoscopy to directly visualize the nasal cavity and sinonasal passages to assess mucosal inflammation, identify polyps, inspect ostiomeatal complexes, and obtain targeted cultures or confirm findings on prior imaging.
The clinical workflow includes: pre-visit review of history and prior imaging, informed consent specific to an office endoscopic nasal examination, topical anesthesia and decongestion of the nasal mucosa, insertion of a rigid or flexible endoscope into one or both nasal cavities to inspect nasal structures, targeted suctioning or culture if indicated, documentation of findings with images or video when performed, and post-procedure counseling. Typical indications include chronic sinusitis (J32.9), nasal polyps (J33.0), acute or recurrent sinusitis (J01.90), nonspecific nasal obstruction (R09.81), and other structural or mucosal disorders of the nasal cavities (J34.89). The procedure is commonly performed by an otolaryngology specialist in an ambulatory clinic or office-based setting and is coded using 31231 for diagnostic endoscopy of the nasal cavity on one or both sides.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
25 | Significant, separately identifiable evaluation and management service by the same physician on the same day | Use when a separate E/M visit is performed and documented on the same day as 31231 for a distinct problem. |
59 | Distinct procedural service | Use when a separate endoscopic or other procedure is performed that is not usually reported with 31231 and documentation supports distinct procedural service. |
52 | Reduced services | Use when the endoscopy is partially reduced or not completed as planned and documentation explains the reduction. |
53 | Discontinued procedure | Use when the procedure is started but terminated due to extenuating circumstances or patient request. |
26 | Professional component | Use when reporting only the professional component separate from a global service when applicable. |
50 | Bilateral procedure | Use when the documentation supports bilateral endoscopic examination and payer requires bilateral modifier instead of separate coding. |
76 | Repeat procedure or service by same physician | Use when the same endoscopic procedure is repeated later the same day by the same physician. |
77 | Repeat procedure by another physician (Note: not in provided list) | Data not available in the input. |
59 | (listed above) | (Duplicate entry avoided) |
22 | Increased procedural services | Use when the procedure required substantially greater work than usual and documentation supports the extraordinary circumstances. |
24 | Unrelated E/M service during a postoperative period | Use when an unrelated evaluation is provided during the global period of a prior surgery. |
78 | Return to the operating room for a related procedure during the postoperative period | Use if a related operative intervention is required in the OR during the postoperative period (rare for diagnostic office endoscopy). |
79 | Unrelated procedure or service by the same physician during the postoperative period | Use when an unrelated procedure is performed during the global period of another surgery. |
59 | (see above) | (see above) |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
207Y00000X | Otolaryngology Physician | Primary specialty performing diagnostic nasal endoscopy. |
207YX0007X | Otolaryngology/Facial Plastic Surgery | Performs diagnostic nasal endoscopy often in preoperative facial plastic evaluation. |
207YX0602X | Otolaryngology/Plastic Surgery within the Head & Neck | Performs nasal endoscopy when integrated with head and neck plastic surgery care. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
J32.9 | Chronic sinusitis, unspecified | Chronic sinonasal inflammation is a common indication for diagnostic nasal endoscopy to evaluate mucosa, ostia, and for polyp identification. |
J34.89 | Other specified disorders of nose and nasal sinuses | Captures structural or mucosal nasal disorders evaluated during endoscopy when a more specific code is not applicable. |
R09.81 | Nasal congestion | Symptom prompting endoscopic assessment to determine obstructive causes such as septal deviation or polyps. |
J01.90 | Acute sinusitis, unspecified | Acute infections of the sinuses may be assessed endoscopically when diagnosis, drainage, or culture guidance is needed. |
J33.0 | Polyp of nasal cavity | Nasal polyps are frequently diagnosed and documented by endoscopic visualization; endoscopy guides management and surgical planning. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
31233 | Nasal/sinus endoscopy, diagnostic | Closely related diagnostic endoscopy code; may be used for additional sinus visualization or when coding conventions distinguish separate endoscopic levels. |
31235 | Nasal/sinus endoscopy, diagnostic | Alternate or additional diagnostic endoscopy code for nasal/sinus evaluation; used per documentation and payer coding rules to reflect extent or technology of the examination. |