Antibody Tests for Neurologic Diseases — CPB 0340 | AETNA Coverage Update

Aetna modified CPB 0340 for neurological antibody testing, effective October 31, 2025. Here's what billing teams need to do.

Aetna, a CVS Health company, updated its antibody tests for neurologic diseases coverage policy under CPB 0340 in the Aetna system. This update affects 21 CPT codes — including 86041, 86051, 86052, 86053, 86362, 86363, 86366, 0431U, 0432U, 0545U, and 0546U — tied to testing for conditions ranging from myasthenia gravis and NMOSD to MOGAD and Lambert-Eaton myasthenic syndrome. If your practice bills neurological antibody panels for Aetna members, the effective date of October 31, 2025 is the line you need to work from.

Quick-Reference Table

Aetna Neurological Antibody Testing Coverage Criteria and Medical Necessity Requirements 2025

The core structure of this Aetna neurological antibody testing coverage policy is a three-part conjunctive test. All three criteria must be met — not two of three, all three. If you're used to submitting these claims based on clinical suspicion alone, this policy will generate denials.

For paraneoplastic neurologic disorders, the member must display clinical features of the condition. The test result must directly affect the treatment being delivered. And after history, physical exam, and conventional diagnostic studies, the diagnosis must remain uncertain. Only then does Aetna consider testing for the suspected antibody medically necessary.

The covered antibodies in the paraneoplastic bucket include anti-Hu (ANNA-1), anti-Yo (APCA-1), anti-Ri (ANNA-2), anti-CV2/CRMP5, anti-amphiphysin, anti-Ma (MA1, MA2), anti-Tr, anti-VGCC, anti-VGKC, anti-AChR, anti-nAChR, anti-recoverin, anti-bipolar cells of the retina, and anti-KLHL11. That's a specific list. If you're testing for an antibody not on it, medical necessity doesn't apply under this bucket.

For general neurologic diseases, the same three-part test applies. The covered antibodies here include anti-AChR, anti-MUSK, anti-MAG, anti-GAD, anti-GM1, anti-GM2, anti-GD1a, anti-GD1b, anti-GQ1b, anti-GT1a, anti-La, anti-Ro, anti-asialo-GM1, anti-SGPG, anti-sulfatide, and anti-VGCC. Some antibodies — like anti-VGCC and anti-AChR — appear in both lists. That overlap matters for how you document the clinical scenario.

Beyond those two main buckets, Aetna separately covers several condition-specific tests when their individual criteria are met:

The MOGAD criteria deserve particular attention. Aetna lists four specific clinical presentations that should raise suspicion: bilateral optic neuritis with anterior optic pathway involvement and optic disc edema; ADEM or ADEM-like presentations with large T2 lesions in the brain and spinal cord; unilateral cortical encephalitis with specific cortical findings; and complete (rather than partial) spinal cord involvement. Your documentation needs to reflect these presentations — not just a diagnosis code.

Prior authorization requirements are not explicitly enumerated in this policy update, but the three-part medical necessity test functions as a de facto documentation standard. If prior auth is triggered on any of these codes for your Aetna contracts, you need that documentation ready before the auth request goes in.

Aetna Neurological Antibody Testing Exclusions and Non-Covered Indications

The policy signals that several codes sit in a different coverage tier — specifically CPT codes 83519, 83520, 84182, 84238, 86235, and 86255, which are grouped under "Electrodiagnostic testing for myasthenia gravis — No specific [coverage designation listed]." That phrasing in the source data is ambiguous. These codes aren't cleanly labeled as covered or excluded — they're in a liminal category.

The real issue here is that Aetna's policy structure separates electrophysiology-adjacent testing from the antibody panels covered in the main criteria. If your team bills 83519 or 83520 for LEMS antibody detection, you're in a gray zone. The policy text does reference these for LEMS confirmation, but the code grouping label suggests coverage is not unconditional.

If you're billing these codes for Aetna members, talk to your compliance officer before October 31, 2025. Don't assume the clinical indication alone will carry the claim.

Coverage Indications at a Glance

Aetna Neurological Antibody Testing Billing Guidelines and Action Items 2025

1. Audit your current charge capture against the approved antibody lists before October 31, 2025.
Pull every claim from the past 12 months where you billed CPT 83516, 86041–86043, 86051–86053, 86362, 86363, or 86366 for Aetna members. Check whether the antibody tested appears on the covered list for the applicable condition bucket. If it doesn't, you have a denial risk starting on the effective date.

2. Update documentation templates to capture all three medical necessity criteria.
Your ordering physician's notes need to explicitly document clinical features, how the test result will change treatment, and what conventional diagnostic workup was completed before ordering. A standard lab order doesn't cut it here. Build a structured note template that maps to Aetna's three-part test.

3. Separate your MOGAD documentation from your NMOSD documentation.
These are two different conditions with two different coverage pathways. Serum MOG-IgG testing for MOGAD (CPT 86362, 86363) requires documentation of one of four specific clinical presentations. Anti-AQP4 testing for NMOSD (CPT 86051, 86052, 86053) has its own pathway. Don't conflate them on the claim — mismatched ICD-10 and CPT pairings trigger denials.

4. Flag repeat MOG testing for review before submission.
CPT 86363 carries a note in the policy data indicating it is "not covered for repeat MOG testing." If your neurology team orders follow-up MOG panels, those claims need clinical justification review before they go out. Build a claim denial prevention step into your workflow for 86363 repeats.

5. Resolve the gray-zone codes before the effective date.
CPT codes 83519, 83520, 84182, 84238, 86235, and 86255 sit in an ambiguous group in this policy. Some have clear clinical coverage indications in the narrative — 83519 and 83520 for LEMS, 86235 for scleroderma — but the code grouping label is unclear. Get clarification from your Aetna provider representative or your billing consultant before submitting claims on these codes for neurologic indications after October 31, 2025.

6. Check ICD-10 pairing for folate receptor antibody testing.
CPT 0399U for the FRAT test maps to E53.8 (cerebral folate deficiency syndrome). If your team has been using a different diagnosis code — or using this code for broader nutritional workups — update your charge capture now. The reimbursement hinges on the right ICD-10 pairing.

CPT, HCPCS, and ICD-10 Codes for Neurological Antibody Testing Under CPB 0340

Covered CPT Codes (When Selection Criteria Are Met)

Codes Requiring Additional Scrutiny (Ambiguous Coverage Group)

Key ICD-10-CM Diagnosis Codes