CPT® Code 31575

Last Updated: February 2026 | Verified for 2026 AMA, CPT & CMS Guidance (Global Surgery, NCCI, OPPS/ASC)

Quick Reference:

• What 31575 means: Diagnostic flexible fiberoptic laryngoscopy to visualize the larynx (and typically adjacent upper aerodigestive structures reached by the flexible scope) to evaluate symptoms such as dysphonia/hoarseness, airway complaints, cough, throat discomfort, and related concerns. The code represents the procedure (scope exam), not a separate E/M service.

• Global period: Medicare classifies many endoscopies/minor procedures as 0-day global. In a 0-day global service, a same-day visit is generally not separately payable unless it is significant and separately identifiable. This is the practical foundation for when modifier 25 is (and is not) appropriate.

• Modifier 25 is not automatic: Reporting an office/outpatient E/M with 31575 requires documentation of a distinct, medically necessary evaluation that goes beyond the typical pre-procedure assessment inherent to performing the laryngoscopy. MAC guidance emphasizes documentation support as the determinant for modifier 25 payment.

• NCCI bundling is the main denial driver: When multiple endoscopic services are performed on the same date, payer edits (including Medicare NCCI) often treat portions of nasal and nasopharyngeal evaluation as integral to a transnasal flexible laryngoscopy. Separate reporting of nasal endoscopy (31231) or nasopharyngoscopy (92511) requires a true distinct service with clear documentation (separate scope, separate anatomical focus, and separate indication when applicable).

• Coverage is indication-driven: Medicare generally applies “reasonable and necessary” principles locally; commercial coverage criteria commonly require documented symptoms or suspected pathology and note that fiberoptic flexible laryngoscopy is appropriate when indirect examination is inadequate to evaluate clinically relevant complaints.

• Facility vs office billing: In hospital outpatient/ASC settings, the facility typically bills under OPPS/ASC groupings while the physician bills professional services as applicable (often with modifier 26 when billing only the professional component). OPPS status indicators and APC assignments are published in CMS addenda. CPT 31575 (diagnostic flexible laryngoscopy) is a high-volume ENT procedure and a frequent audit target primarily for two reasons:

• same-day E/M overbilling (modifier 25 applied reflexively), and

• unbundling when multiple endoscopic codes are billed together without documentation establishing a truly distinct service. The most defensible approach is to make the chart answer three payer questions: Why was flexible laryngoscopy medically necessary today? What exactly was examined and found? and Were any additional billed services truly separate from the laryngoscopy and separately documented?

This guide presents a 2026 payer-realistic framework anchored in CMS global surgery rules, the Medicare NCCI policy manual, and authoritative specialty and payer guidance.

1. Clinical Definition and Procedure Scope

CPT 31575 describes a diagnostic flexible fiberoptic laryngoscopy. Operationally, the clinician advances a flexible endoscope (often transnasal, sometimes transoral) to evaluate the larynx and adjacent structures accessible by the scope as clinically necessary. The service is used to assess abnormalities suggested by symptoms (e.g., persistent dysphonia/hoarseness), physical findings, or prior tests, and it is commonly performed in the office with topical anesthesia.

A payer-auditable record should make clear that this was a diagnostic examination (not a therapeutic or operative endoscopy). If the encounter includes intervention (for example, biopsy or removal of a lesion) the correct code family changes, and 31575 may no longer be the correct single code for what occurred. Even when an intervention is not performed, documentation should identify the anatomical regions visualized and key observations that support the clinical decision-making that followed.

Practical scope boundary: When multiple endoscopic evaluations are billed together on the same date (e.g., nasal endoscopy and laryngoscopy), auditors focus on whether the additional code represents a distinct procedure or whether it duplicates integral portions of the flexible laryngoscopy pathway (especially when performed transnasally).

2. Common Indications and Medical Necessity

Medical necessity for 31575 is typically supported by symptoms, abnormal exam findings, or concern for pathology requiring visualization beyond what can be assessed with indirect examination. In routine ENT practice, common indications include persistent hoarseness/dysphonia, suspected laryngeal lesion, airway symptoms (e.g., stridor), chronic cough with suspected upper airway contribution, and dysphagia/aspiration concerns when structural or functional laryngeal assessment is needed.

Commercial coverage criteria commonly describe diagnostic fiberoptic flexible laryngoscopy as medically necessary when there are relevant voice, swallowing, or airway complaints and when indirect evaluation is inadequate or insufficient to answer the clinical question. While Medicare does not typically issue a single national coverage policy for CPT 31575 alone, the same “reasonable and necessary” logic is operationalized through documentation review, diagnosis-code plausibility, and edit logic.

• Voice complaints: persistent hoarseness/dysphonia, voice fatigue, suspected vocal fold pathology.
• Airway complaints: stridor, dyspnea with suspected upper airway obstruction, episodic laryngospasm concerns.
• Throat symptoms: chronic throat discomfort, globus sensation when laryngeal evaluation is clinically indicated.
• Swallowing concerns: dysphagia/aspiration suspicion when laryngeal structural evaluation informs next steps.
• Lesion surveillance or evaluation: suspected mass, lesion, or abnormality needing direct visualization.
• Perioperative assessment: pre- or postoperative vocal fold function assessment when clinically justified and documented. The most defensible medical-necessity documentation is specific rather than generic. “Hoarseness” alone is less audit-resilient than “hoarseness for 6 weeks with occupational voice demand, failed conservative measures, and concern for vocal fold lesion.” The payer question is not whether laryngoscopy can be clinically useful; it is whether the record explains why it was necessary on that date for that patient.

3. Global Period, Same-Day E/M, and Modifier 25

Medicare’s global surgery framework is central to billing 31575 correctly. Many endoscopies and minor procedures are treated as 0-day global, meaning there is no postoperative period and the typical same-day visit related to the procedure is generally not paid separately. CMS guidance explains that a visit on the procedure day is generally not payable as a separate service when it is related to the procedure itself.

This is where modifier 25 becomes relevant: if the clinician performs a significant, separately identifiable E/M service on the same day as 31575, the E/M may be separately reportable with modifier 25—but only when the documentation supports it. MAC guidance and payer education materials consistently emphasize that modifier 25 is documentation-driven, not a routine append for every scoped visit.

3.1 What “separately identifiable” looks like in a laryngoscopy visit

In practical terms, the E/M is most defensible when it includes work that is not merely preparation for the scope. Examples include evaluation and management of additional problems, a comprehensive assessment that materially changes management beyond the laryngoscopy findings, medication management decisions unrelated to the procedure, or separate diagnostic reasoning documented before the procedure note. The key is that the E/M note can stand alone as medically necessary even if the laryngoscopy had not been performed.

3.2 Common modifier 25 failure pattern

A frequent audit pattern is a short note that consists primarily of the complaint, minimal exam, and the laryngoscopy findings—followed by billing an E/M with modifier 25. Under global surgery concepts, the minimal pre-procedure evaluation and the procedure itself are not two separately payable services unless the record demonstrates a distinct E/M that is significant and separately identifiable.

Documentation rule that prevents denials: If billing an E/M with modifier 25 on the same date as 31575, maintain documentation that clearly distinguishes (a) the E/M assessment and decision-making and (b) the procedure note. This separation is often easiest to defend when the E/M contains a complete assessment/plan, while the laryngoscopy note focuses on consent/technique/findings.

4. Medicare and Commercial Coverage Practicalities

For Medicare, coverage is generally governed by the overarching “reasonable and necessary” standard and implemented through claim edits, documentation review, and local contractor policies. Noridian’s MAC guidance on minor surgery and endoscopies is commonly used as an operational reference for how Medicare treats related services around a minor procedure (including same-day visits).

Commercial plans often publish specific medical policies describing when diagnostic flexible laryngoscopy is considered medically necessary (for example, to evaluate significant voice, swallowing, or airway complaints, and when indirect evaluation is insufficient). Such policies are frequently used for prior authorization frameworks and retrospective audits.

Practical implication: the coding may be “right” yet still deny if the record does not clearly connect symptoms and clinical rationale to the procedure performed. Your best defense is an order/note that is explicit about the reason the flexible scope was required to evaluate the presenting complaint.

5. NCCI Edits, Bundling, and “Same-Day Scope” Pitfalls

Medicare’s National Correct Coding Initiative (NCCI) policy manual is the primary source for understanding bundling and correct reporting of multiple procedure codes. NCCI policy reflects the principle that when one service is integral to another, separate reporting is generally not appropriate unless a distinct service was performed and appropriately documented.

5.1 31575 and nasal endoscopy (31231) on the same date

The most common controversy in ENT coding for 31575 involves billing diagnostic nasal endoscopy (31231) on the same date. Specialty guidance emphasizes that when a flexible laryngoscopy is performed transnasally, portions of nasal evaluation may be inherent in the approach, and separate reporting can create an unbundling risk unless there is clear evidence of a distinct nasal endoscopy performed for a distinct purpose. The AAO-HNS coding guidance on nasal endoscopy and laryngoscopy performed on the same date is widely cited for operational clarity in this scenario.

When separate billing is appropriate, documentation should specify: (1) separate indication(s), (2) the distinct anatomical target of the nasal endoscopy (e.g., evaluation of sinus outflow tract, postoperative sinus cavity surveillance), and (3) procedure details supporting that it was performed as a separate diagnostic service rather than incidental visualization during laryngoscope passage. NCCI still governs bundling logic; specialty guidance helps determine when the case is legitimately distinct.

5.2 31575 and nasopharyngoscopy (92511) on the same date

Similar bundling concerns arise when billing 92511 (nasopharyngoscopy) with 31575. Clinically, a flexible laryngoscopy may include visualization of the nasopharyngeal corridor during passage depending on technique. NCCI principles treat integral components as bundled unless a distinct procedure is performed and documented. The safe operational rule is to avoid dual reporting unless there is an unusual and clearly documented reason for a separate nasopharyngoscopy as an independent service.

5.3 Key compliance principle

NCCI policy is not “modifier-driven”; it is documentation-driven. Modifier 59 (or an appropriate X modifier) is justified only when the record supports a distinct procedural service. The NCCI manual is explicit that correct coding requires reporting the most appropriate code combination and avoiding unbundling.

6. Modifier Use (25, 59/X, 26) and When Not to Use Them

6.1 Modifier 25 (E/M)

Use modifier 25 on the E/M service only when the same-day E/M is significant, separately identifiable, and supported by documentation distinct from the procedure work. Medicare contractor guidance reinforces that documentation is the determinant for payment when modifier 25 is reported with a minor procedure.

6.2 Modifier 59 / X{E,S,U,P} (distinct procedural service)

Use modifier 59 (or payer-accepted X modifiers) only when reporting two procedures that would otherwise be bundled but were truly distinct (different anatomical site/structure, separate encounter, or separate, independent service). For ENT endoscopic combinations, the defensibility hinges on separate indication and separate procedural performance rather than “we looked at both.” NCCI is the controlling policy baseline for Medicare bundling principles.

6.3 Modifier 26 (professional component)

In facility settings (hospital outpatient or ASC), the facility typically bills the technical resources under OPPS/ASC rules while the physician bills professional services. Where applicable, modifier 26 is used to indicate professional component billing. Specific component rules depend on payer contracts and claim type, but the general Medicare approach to facility payment classifications is reflected in OPPS addenda and status indicators.

Do not use modifiers to “force pay”: Modifier 25 and modifier 59/X modifiers are common audit triggers when applied routinely. Use them only when the record supports the required distinctness and when the additional billed service is actually separately payable under the applicable payer policy.

7. Facility vs Non-Facility Billing and OPPS/ASC Considerations

Where 31575 is performed changes how the claim is built and how payment is split. In an office (non-facility) setting, the practice typically bills the global service when it owns the equipment and supplies and provides the clinical labor. In hospital outpatient or ASC settings, the facility bills its component under OPPS/ASC rules, while the physician bills professional services as appropriate. CMS publishes OPPS status indicators and APC groupings in quarterly addenda (Addendum B is the standard operational reference for code-to-APC/status mapping).

Practical compliance point: component mismatches create duplicate denials. A clean approach is to define in advance who bills which component in each setting and to align charge capture with that policy.

8. Documentation Standards (Audit-Proofing)

Documentation for 31575 should be built to withstand two predictable payer review pathways: (1) medical necessity review (was the procedure justified?), and (2) unbundling review (were other billed services distinct?). The documentation also must support same-day E/M reporting when modifier 25 is used.

8.1 Minimum documentation elements for 31575

• Indication/medical necessity: symptom duration, severity, red flags, prior evaluation, and why flexible laryngoscopy was needed.
• Consent and preparation: topical anesthesia used (if any), patient tolerance, route (transnasal/transoral).
• Scope pathway and structures visualized: identify the key anatomical regions assessed to support that a laryngeal diagnostic endoscopy was performed.
• Findings: descriptive findings (e.g., edema/erythema, lesions, mobility, asymmetry) tied to the clinical question.
• Assessment/plan: how findings affected management (treatment, further imaging, referral, follow-up, biopsy planning).

8.2 Documentation to support an E/M with modifier 25

If billing E/M + 31575 on the same date, document the E/M as its own medically necessary service. CMS global surgery guidance makes clear that same-day visits related to the minor procedure are generally not separately payable; contractor guidance emphasizes that modifier 25 payment requires documentation support.

• Separate problem-oriented evaluation: document history/exam/MDM that goes beyond typical pre-scope work.
• Separate assessment and management: decisions about additional conditions or management steps not limited to “performed scope.”
• Clear separation in the note: many practices use a separate “Procedure Note” section for the laryngoscopy.

8.3 Documentation to support billing multiple endoscopies on the same date

When billing 31575 with another endoscopic code (e.g., nasal endoscopy), specialty guidance and NCCI principles point to the same core requirement: show that the second service was distinct and medically necessary. AAO-HNS guidance provides ENT-specific best practices for documenting when nasal endoscopy and laryngoscopy occur on the same date.

Audit-proofing tactic: If two endoscopic procedures are legitimately performed, consider separate procedure notes (or separate headings) with distinct indications and distinct findings, and ensure diagnosis linkage on the claim corresponds to each distinct indication.

9. Comparison Table: 31575 vs Related Endoscopy Codes

10. Real-World Coding Scenarios

Scenario 1: Chronic hoarseness, office laryngoscopy only

Setting: ENT office (non-facility).

Service: Patient with persistent dysphonia; physician performs diagnostic flexible laryngoscopy with documented findings and plan.

Coding logic: Report 31575 only unless the record supports a separate significant E/M beyond the inherent pre-procedure evaluation.

Documentation tip: Document symptom duration, relevant risk factors, and specific laryngoscopy findings that drove management.

Scenario 2: Same-day E/M + laryngoscopy (modifier 25 supported)

Setting: ENT office.

Service: Patient presents with multiple issues (e.g., dysphonia plus separate otologic complaint requiring evaluation and management); clinician performs a significant problem-oriented E/M and separately performs laryngoscopy.

Coding logic: Report appropriate E/M with modifier 25 plus 31575 when documentation clearly supports the separate E/M per global surgery principles.

Documentation tip: Keep the E/M assessment/plan distinct from the procedure note and avoid “procedure-driven” notes that cannot stand alone.

Scenario 3: Nasal endoscopy and laryngoscopy on the same date

Setting: ENT office.

Service: Patient has distinct nasal/sinus symptoms and separate voice complaint; clinician performs diagnostic nasal endoscopy for nasal indication and flexible laryngoscopy for laryngeal indication.

Coding logic: Dual billing can be defensible only when documentation establishes distinct indications and distinct services, consistent with ENT specialty guidance and NCCI distinctness principles (and modifiers are used only when appropriate).

Documentation tip: Use separate procedure documentation segments and link each procedure line to the diagnosis that justified it.

Scenario 4: Hospital outpatient laryngoscopy (component billing awareness)

Setting: Hospital outpatient department.

Service: ENT performs diagnostic flexible laryngoscopy while the facility provides technical resources.

Coding logic: Facility bills under OPPS rules; physician bills professional services as appropriate (often with professional component conventions). OPPS status and APC assignment are published by CMS in addenda.

Documentation tip: Ensure the physician report is complete and signed; component errors are a common source of denials.