ModifiedPremera BluecrossPolicy M2172

Onychomycosis testing (NAAT and related diagnostic tests)

Defines coverage for nucleic acid amplification testing and related laboratory diagnostics for onychomycosis (fungal nail infection), specifying when NAAT is reimbursable and diagnostic tests and codes addressed. Applies to clinical providers ordering tests for members covered by this payer policy.

Policy Summary

PayerPremera Bluecross

PolicyOnychomycosis testing (NAAT and related diagnostic tests)

Policy CodePolicy M2172

Change TypeConditional reimbursement exception added

Effective DateFeb 6, 2026

Next Review Date

Key ActionOrder NAAT only for unresolved onychomycosis after failed antifungal therapy and document prior treatment failure when requesting reimbursement.

SourceLink

POLICY UPDATE CHANGES

Nucleic acid amplification testing may be considered reimbursable for individuals with unresolved onychomycosis after failed anti-fungal treatment, but not for initial screening, diagnosis, or confirmation of the condition.

After treatment failureNAAT stance

Not for screening/diagnosisExclusion

7 codesCPT group

83%PCR sensitivity

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Implementation notice

Coverage Criteria for NAAT

inv-01: Reimbursable NAAT — Covered when ALL of the following are met

Covered when ALL of the following are met:

NAAT after therapy failure: Member has a clinical diagnosis of onychomycosis AND antifungal therapy has failed to resolve the infection

NAAT is considered reimbursable in this circumstance

inv-02: Non-reimbursable NAAT — Not covered when ANY of the following are true

Not covered when ANY of the following are true:

NAAT for screening/diagnosis: NAAT is used to screen for, diagnose, or confirm onychomycosis (initial diagnostic use)

NAAT for these purposes is not reimbursable and may be denied

inv-03: NAAT reimbursement criteria — detailed conditional logic for reimbursement

Covered when ALL of the following are met:

NAAT after failed therapy: Nucleic acid amplification testing (NAAT) for onychomycosis may be considered reimbursable only for individuals with unresolved onychomycosis after failed antifungal treatment

NAAT is NOT reimbursable for initial screening, diagnosis, or confirmation of onychomycosis; documentation should support prior antifungal therapy and continued unresolved disease

NAAT used to screen for, diagnose, or confirm onychomycosis is not reimbursable.

Nucleic acid amplification testing (NAAT) is not reimbursable for initial screening, diagnosis, or confirmation of onychomycosis.

Use of NAAT for the purposes of initial screening, diagnosis, or confirmation of onychomycosis is considered not reimbursable under this policy.

The policy excludes reimbursement for NAAT when performed for initial evaluation (screening, diagnosis, or confirmation) of onychomycosis.

When NAAT May Be Reimbursed

inv-26: Onychomycosis with persistent infection after antifungal therapy — NAAT may be reimbursed to evaluate persistent infection or species identification after treatment failure

NAAT may be reimbursed to evaluate persistent infection or for species identification when the following are met:

Persistent infection after therapy: Member has onychomycosis with persistent or unresolved infection despite a trial of appropriate antifungal therapy

Used to evaluate persistent infection or to identify organism when treatment failure has occurred

Supporting documentation: Clinical documentation indicates prior antifungal therapy and continued clinical disease (unresolved onychomycosis)

Documentation should be provided when requesting NAAT under this exception

inv-27: Clinical suspicion of onychomycosis (discolored, dystrophic, brittle nail or onycholysis) — recommendation for lab confirmation

Laboratory confirmation is recommended when the following clinical features are present:

Provider Responsibilities and Documentation

Denial Risk

NAAT usage and reimbursement restrictions

NAAT is reimbursable only for individuals with unresolved onychomycosis after an adequate trial of anti-fungal therapy has failed. NAAT performed to screen for, diagnose, or confirm onychomycosis (including initial testing) is not reimbursable and claims may be denied.

Reimbursable only after failed antifungal therapy
Not reimbursable for initial screening/diagnosis/confirmation

Documentation Required

Risk if no laboratory confirmation

Laboratory confirmation is recommended before initiating systemic antifungal therapy because treatment without lab confirmation risks inappropriate therapy, unnecessary exposure to drug adverse effects, missed alternative diagnoses (nail dystrophy), and failure to identify mixed or less responsive infections. Document laboratory testing and results when available.

Relevant CPT and Laboratory Codes

Listed CPT Codes (NAAT and related)CPT

87149	Culture, typing; identification by nucleic acid (DNA or RNA) probe, direct probe technique, per culture or isolate, each organism probed
87480	Infectious agent detection by nucleic acid (DNA or RNA); Candida species, direct probe technique
87481	Infectious agent detection by nucleic acid (DNA or RNA); Candida species, amplified probe technique
87482	Infectious agent detection by nucleic acid (DNA or RNA); Candida species, quantification
87798	Infectious agent detection by nucleic acid (DNA or RNA), not otherwise specified; amplified probe technique, each organism
87800	Infectious agent detection by nucleic acid (DNA or RNA), multiple organisms; direct probe(s) technique
87801	Infectious agent detection by nucleic acid (DNA or RNA), multiple organisms; amplified probe(s) technique

Ordering and Frequency Guidance

Note

Ordering: use clinical evaluation + standard mycologic tests first

Diagnosis should rely on clinical evaluation plus standard mycologic tests (KOH, fungal culture, PAS); molecular tests (NAAT/PCR) are adjunctive and appropriate particularly after initial therapy failure.

Billing Rule

Ordering and specimen collection may be performed by treating provider

Healthcare providers may collect small nail or skin scrapings for testing; the policy does not specify limits on who may order tests but implies usual ordering by the treating provider or laboratory.

Documentation Required

Ordering must indicate prior failed antifungal treatment

Services and Uses Not Covered

Nucleic acid amplification testing performed to screen for, diagnose, or confirm onychomycosis is not covered by this policy.

Although PCR techniques can be useful for confirming onychomycosis, some guidance has concluded these methods were not cost-effective enough for general use and therefore not routinely recommended.

NAAT for initial screening, diagnosis, or confirmation of onychomycosis is explicitly excluded from reimbursement under this policy.

Key Definitions

NAAT (nucleic acid amplification testing)

DefinitionNucleic acid amplification testing (NAAT): laboratory methods for detecting microbial DNA or RNA, including polymerase chain reaction (PCR), PCR–RFLP (restriction fragment length polymorphism), and next‑generation sequencing (NGS)

Common methodsExamples listed in policy terminology: PCR, PCR‑RFLP, and NGS

Context of useNAAT is referenced as molecular testing that can increase sensitivity and speed of species identification when used with culture

OSI — Onychomycosis Severity Index

DefinitionOnychomycosis Severity Index (OSI): a scoring system referenced in terminology for grading onychomycosis severity

Scoring componentsOSI is based on area of nail involvement and proximity to the matrix, with additional points for dermatophytoma or marked subungual hyperkeratosis (as described in policy definitions)

Background and Evidence Summary

Onychomycosis (tinea unguium) is a fungal infection of the nail predominantly caused by dermatophytes such as Trichophyton rubrum and Trichophyton mentagrophytes, though yeasts and non-dermatophyte molds may also be responsible. Toenails are affected more commonly than fingernails. Diagnosis typically combines clinical assessment (discoloration, dystrophy, brittleness, or onycholysis) with mycologic testing; standard laboratory methods include KOH preparation, fungal culture, and PAS-stained histology, while molecular methods (NAAT/PCR, NGS) can increase sensitivity and speed of organism identification.

Frequency Limits

Frequency limits (placeholder)

Frequency limits placeholderNo specific frequency limits stated in policy; reserved for any future frequency constraints

Policy noteFrequency_limits entry in brief is empty — policy does not define a test repetition interval

Ordering implicationWhen present, frequency limits would be applied per member benefit plan or prior authorization rules; none are specified here

Policy Revision History

2025-11-01policy_additionLatest

New policy approved October 14, 2025 establishing that NAAT may be reimbursable for individuals with unresolved onychomycosis after failed antifungal treatment but is not reimbursable for initial screening, diagnosis, or confirmation; effective February 6, 2026 following 90-day provider notification.

Policy Summary

PayerPremera Bluecross

PolicyOnychomycosis testing (NAAT and related diagnostic tests)

Policy CodePolicy M2172

Change TypeConditional reimbursement exception added

Effective DateFeb 6, 2026

Next Review Date

Key ActionOrder NAAT only for unresolved onychomycosis after failed antifungal therapy and document prior treatment failure when requesting reimbursement.

SourceLink

On This Page

Clinical features suggesting onychomycosis: Discolored, dystrophic, or brittle nail OR nail with onycholysis

Multiple specialty guidelines recommend laboratory confirmation prior to initiating treatment

Purpose of confirmation: Laboratory confirmation is sought to differentiate fungal from nonfungal nail disease and to enable species identification when treatment selection depends on organism

Preferred initial tests include KOH and/or culture; PCR may be adjunctive

inv-28: Unresolved onychomycosis after failed antifungal treatment — NAAT may be considered reimbursable

NAAT may be considered reimbursable when ALL of the following are true:

Unresolved disease after treatment: Member has unresolved onychomycosis after an adequate trial of antifungal treatment

Policy establishes NAAT reimbursement only for unresolved cases after failed therapy

Prior diagnostic evaluation: Standard mycologic testing (e.g., KOH, fungal culture, PAS) has been performed or documented as attempted prior to NAAT when feasible

Diagnostic testing is generally recommended before treatment; documentation expected when seeking reimbursement

Clinical justification provided: Ordering documentation specifically indicates NAAT is requested for evaluation of persistent infection or species identification following treatment failure

Prior authorization may be required per member benefit plan

Risk of inappropriate therapy or missed nonfungal diagnoses if no laboratory confirmation

Society guidance recommends laboratory confirmation prior to treatment when feasible

Documentation Required

Prior therapy and diagnostic documentation expectations

Prior to NAAT reimbursement, documentation should demonstrate an adequate trial of standard therapy and prior diagnostic evaluation. Providers should include dates and details of antifungal treatment, response to therapy, and prior mycologic testing (e.g., KOH, fungal culture, PAS) in the medical record and claim documentation.

Documented trial of antifungal therapy with start/stop dates and clinical response
Prior mycologic testing results (KOH, culture, PAS) when available
Clinical notes describing persistent or worsening disease despite therapy

Step Therapy

Therapy-first requirement and empiric treatment notes

A therapy-first approach is required for NAAT reimbursement: NAAT is intended as an adjunct when disease remains unresolved after appropriate antifungal treatment and standard diagnostic methods have been attempted or are non-diagnostic. Empiric treatment without prior testing may be reasonable only in select cases (e.g., cost-prohibitive testing) per clinical judgment and guideline exceptions; however, NAAT still will not be reimbursed as an initial diagnostic or screening test.

Therapeutic trial failure required before NAAT is eligible for reimbursement
Empiric terbinafine may be considered when testing is cost-prohibitive, but this does not make subsequent NAAT reimbursable for initial diagnosis
LDT/NAAT assays may be laboratory-developed tests regulated under CLIA; FDA clearance is not required for clinical use but documentation of test type may be requested

When ordering NAAT for an unresolved case, the request should indicate prior failed antifungal treatment to support coverage under the policy exception.

Severity rangesOSI ranges classify disease as mild, moderate, or severe (policy terminology lists OSI as the defined index)

Onychomycosis

DefinitionOnychomycosis: the technical term for a fungal nail infection, which can be caused by dermatophytes, yeasts, or other fungi

Affected sitesCan affect fingernails or toenails; toenail involvement is more common

Specimen guidanceCDC notes healthcare providers may take a small skin scraping or nail sample for testing

NAAT (alternate references)

Alternate definition sourceNAAT is referenced in the policy terminology table and in multiple references describing molecular identification methods (including commercial multiplex PCR and other molecular assays)

Examples in literatureReferences cite various molecular identification methods and commercial kits (e.g., Euroarray dermatomycosis, multiplex PCR) as NAAT applications

Regulatory contextNAAT methods include both commercial assays and laboratory-developed tests which must meet laboratory validation standards cited elsewhere in the policy