Obtain authorization and ensure medical necessity

Services must meet authorization and medical necessity guidelines and coverage depends on the member's benefit coverage; authorization may be required per the member contract. Providers are responsible for submitting accurate documentation and proper coding to support authorization and reimbursement.

• Coverage depends on individual benefit coverage and may require authorization per member contract.
• Claims may be denied or recouped if coding/billing guidelines or current reimbursement policies are not followed.

Request prior authorization only for guideline-supported indications

Prior authorization should confirm the test is aligned with guideline-based indications (for example, evaluation of suspected small-fiber neuropathy such as painful/burning feet of unknown origin) and that results would affect patient management.

• Prior authorization should ensure testing aligns with guideline-based indications such as evaluation of suspected small fiber neuropathy.
• Skin biopsy may be considered for diagnosis of distal symmetric polyneuropathy, particularly small-fiber sensory neuropathy (SFSN).

Bill using the policy-listed CPT codes for biopsy analysis

When billing laboratory services associated with skin biopsy analysis, use the CPT codes listed for histology, immunohistochemistry, immunofluorescence, and morphometric analysis; include the appropriate code(s) for initial and additional antibody stains and morphometric nerve analysis.

• Use CPT codes 88342, 88344, 88346 for immunohistochemistry/immunocytochemistry procedures as listed.
• Use CPT codes 88350 and 88356 for immunofluorescence procedures and include morphometric analysis code when applicable.

Perform noninvasive initial testing first

Before ordering IENFD/CCM, perform or document noninvasive bedside assessments and autonomic testing as appropriate (e.g., 10-g monofilament, 128-Hz tuning fork, temperature or pinprick testing); these simple tests are recommended as initial evaluation per guideline statements.

• Perform 10-g monofilament and 128-Hz tuning fork testing and document results.
• Consider temperature or pinprick testing and autonomic testing prior to or alongside skin biopsy when clinically indicated.

Provide full clinical documentation to support medical necessity

Submit clinical documentation demonstrating symptoms, physical exam findings, and diagnostic testing that meet all coverage criteria for IENFD testing; documentation must show painful sensory neuropathy, absence of disorders that predispose to painful neuropathy, lack of large-fiber exam findings, and normal EMG/NCS when applicable.

• Document symptoms of painful sensory neuropathy.
• Document absence of predisposing disorders (e.g., diabetes, toxic, HIV, celiac, inherited neuropathy).
• Document physical exam showing no large-fiber findings (reduced/absent reflexes, reduced proprioception/vibration).
• Attach electromyography and nerve-conduction study results showing no large-fiber neuropathy.

Document specific small‑fiber signs and prior testing

Clinical notes must specifically document signs or symptoms of small-fiber dysfunction to justify biopsy (for example, painful/burning feet, impaired temperature or pinprick sensation, or autonomic dysfunction) and should reference prior bedside testing per guideline recommendations.

• Record symptoms such as painful or burning feet and objective small-fiber deficits (temperature or pinprick loss).
• Document prior bedside testing (10-g monofilament, 128-Hz tuning fork) and any autonomic testing performed.
• Reference relevant guideline recommendations (EFNS/PNS, AAN/AANEM/AAPM&R, ADA) when justifying IENFD or CCM.

Provide lab validation and CPT coding details

Include laboratory validation and procedure coding information with claims: note if IENFD testing was performed as a laboratory-developed test (LDT) validated in-house under CLIA and submit the histology/immunohistochemistry and morphometric procedure codes described in the policy.

• Indicate when the test is an LDT validated under CLIA '88 in laboratory documentation.
• Include relevant histology/immunohistochemistry codes (e.g., 88342, 88344, 88346) and immunofluorescence codes (88350, 88356) and morphometric analysis coding on claims and lab reports.

Adhere to coding and documentation requirements to avoid denials

Follow coding and billing guidance exactly and ensure documentation supports billed services; failure to follow coding/billing rules or provide accurate documentation may result in claim denial or recoupment.

• Code claims according to industry standard coding guidelines and the policy's listed procedure codes.
• Ensure documentation supports the medical necessity of billed services to avoid denial or recoupment.

Avoid off‑criteria testing

Tests performed outside the policy's specified coverage criteria are not eligible for coverage and may be denied; ensure the indication matches the policy requirements before ordering or billing.

• Do not perform or bill for skin biopsy IENFD testing for indications not meeting the policy's listed criteria.
• Measurement of sweat gland nerve fiber density does not meet criteria and should not be billed as covered.

Ensure sufficient clinical indication to support testing

If clinical documentation does not show evaluation consistent with guideline-recommended assessment for small-fiber dysfunction (for example, lack of documented clinical impression of SFN or absence of recommended bedside testing), the claim may be denied for insufficient clinical indication.

• Document clinical impression of SFN or painful/burning feet of unknown origin when ordering IENFD.
• Include results of recommended bedside assessments to demonstrate appropriate evaluation prior to biopsy.

Follow government coverage policies when applicable

When a conflict exists between this policy and an applicable government policy (such as a Medicare LCD/NCD or state Medicaid policy), the government policy takes precedence; nonconformance with those policies may trigger denial.

• Check applicable Medicare and state Medicaid policies for members and follow those determinations when they conflict with this policy.
• Nonconformance with government coverage rules can result in denial.