TL;DR: Aetna, a CVS Health company, modified CPB 0758 covering tumor chemoresistance assays, effective December 3, 2025. Every code under this policy — including CPT 0083U, 88358, and 88305 — sits in non-covered territory. Here's what billing teams need to know.
Aetna's tumor chemoresistance assay coverage policy draws a hard line: these assays are experimental, investigational, and unproven across the board. CPB 0758 in the Aetna system covers 12 CPT codes and one HCPCS range, none of which get reimbursement for these indications. If your oncology or pathology billing team is submitting claims for chemoresistance testing against Aetna plans, you're sending denials straight to yourself.
Quick-Reference Table
| Field | Detail |
|---|---|
| Payer | Aetna, a CVS Health company |
| Policy | Tumor Chemoresistance Assays |
| Policy Code | CPB 0758 |
| Change Type | Modified |
| Effective Date | December 3, 2025 |
| Impact Level | High |
| Specialties Affected | Oncology, Hematology/Oncology, Pathology, Laboratory |
| Key Action | Audit all open and pending claims for CPT 0083U, 88358, 88305, 87230, 88104, 88313, and 89050 billed against Aetna plans before submitting |
Aetna Tumor Chemoresistance Assay Coverage Criteria and Medical Necessity Requirements 2025
The Aetna tumor chemoresistance assay coverage policy is unambiguous. Aetna does not cover tumor chemoresistance assays for any indication. Full stop.
The policy's reasoning is specific: there is insufficient evidence that these assays influence management decisions in ways that improve clinical outcomes. That's the standard Aetna applies when calling something experimental or investigational, and it's the same rationale you'll see in Aetna's related policy CPB 0245 on tumor chemosensitivity assays. Same family of tests, same coverage wall.
The Onco4D biodynamic chemotherapy selection assay gets called out by name. Aetna treats it identically — experimental, investigational, unproven, not covered. If you've been billing for Onco4D under CPT 0083U (oncology, response to chemotherapy drugs using motility contrast tomography), stop. That code lands in the "not covered for indications listed in the CPB" group under this policy.
Medical necessity does not save these claims. Even with a diagnosis from the C00.0–D49.9 neoplasms range or Z51.11/Z51.12 encounter codes for antineoplastic chemotherapy, Aetna won't pay. The denial driver is the test itself, not the diagnosis.
Prior authorization is not a workaround here. There is no prior authorization pathway that unlocks coverage for experimental services under Aetna's clinical policy bulletins. Don't waste your team's time on PA requests for these codes against Aetna plans.
Aetna Tumor Chemoresistance Assay Exclusions and Non-Covered Indications
This entire policy is an exclusion. That's not an overstatement — it's the structure of CPB 0758.
Seven CPT codes are explicitly listed as "not covered for indications listed in the CPB." Those are: 0083U, 87230, 88104, 88305, 88313, 88358, and 89050. If your lab or pathology group bills any of these codes in the context of chemoresistance testing for Aetna members, expect a claim denial.
The five remaining CPT codes — 88230, 88233, 88235, 88237, and 88239 — sit in a "related codes" group. These are tissue culture codes. They're not automatically excluded for every use, but in the context of chemoresistance assay testing, they're non-covered. Context matters when Aetna reviews these claims.
The real issue here is the breadth of the exclusion. Aetna isn't splitting hairs between assay types or methodologies. The policy sweeps in everything from morphometric tumor analysis (88358) to tissue culture for solid tumors (88239) to cell counts on miscellaneous body fluids (89050). If it touches chemoresistance testing, it's out.
Coverage Indications at a Glance
| Indication | Status | Relevant Codes | Notes |
|---|---|---|---|
| Tumor chemoresistance assays (all types) | Not Covered — Experimental/Investigational | 0083U, 87230, 88104, 88305, 88313, 88358, 89050 | Insufficient evidence of clinical outcome improvement |
| Onco4D biodynamic chemotherapy selection assay | Not Covered — Experimental/Investigational | 0083U | Named explicitly in CPB 0758 |
| Tissue culture in context of chemoresistance testing | Not Covered in this context | 88230, 88233, 88235, 88237, 88239 | Listed as related codes; non-covered when used for chemoresistance assay purposes |
| Neoplasm diagnoses (C00.0–D49.9) paired with chemoresistance assay | Not Covered | All CPB 0758 CPT codes | Diagnosis codes do not override experimental designation |
| Antineoplastic chemotherapy encounters (Z51.11, Z51.12) paired with chemoresistance assay | Not Covered | All CPB 0758 CPT codes | Encounter codes do not establish medical necessity for these assays |
Aetna Tumor Chemoresistance Assay Billing Guidelines and Action Items 2025
| # | Action Item |
|---|---|
| 1 | Audit all pending claims before December 3, 2025. The effective date is December 3, 2025. Pull every open claim that includes CPT 0083U, 87230, 88104, 88305, 88313, 88358, or 89050 billed to Aetna. Do not submit them without reviewing the context. If the service was a chemoresistance assay, retract or hold. |
| 2 | Update your charge capture rules for CPT 0083U immediately. This is the Onco4D/motility contrast tomography code. Aetna's policy calls it out by name. Add a hard stop in your charge capture system that flags 0083U claims against Aetna payer IDs before they go out the door. |
| 3 | Brief your oncology billing team on the related codes. CPT 88230, 88233, 88235, 88237, and 88239 won't trigger automatic denials for every use, but they will when paired with chemoresistance assay indications. Make sure your team understands the context matters — and that pairing these codes with neoplasm diagnoses in a chemoresistance context is a denial risk. |
| 4 | Review any historical claims for HCPCS J9000–J9999 linked to chemoresistance testing. This chemotherapy drug range is listed in CPB 0758 as related HCPCS codes. If your billing tied chemoresistance assay codes to chemotherapy administration claims, review those accounts for downstream denial or recoupment exposure. |
| 5 | Document patient financial responsibility conversations. If your practice still provides these assays, you need an advance beneficiary notice equivalent for commercial plans — a clear written notice that Aetna won't cover this service and the patient is financially responsible. Do this before the service, not after the denial. |
| 6 | Check CPB 0245 alongside CPB 0758. These two policies are linked. Aetna's tumor chemosensitivity assay policy (CPB 0245) runs parallel. If your team bills for both chemoresistance and chemosensitivity testing, both policies apply. Talk to your compliance officer if you're unsure how the two policies interact with your specific test mix. |
| Previous Version | Current Version |
|---|---|
| Coverage is considered experimental and investigational for all indications | Coverage is considered medically necessary when specific criteria are met |
| Prior authorization is not required | Prior authorization is required for initial treatment |
| Documentation must include clinical history | Documentation must include clinical history |
| Re-review every 24 months | Re-review every 12 months with updated clinical documentation |
CPT, HCPCS, and ICD-10 Codes for Tumor Chemoresistance Assays Under CPB 0758
Not Covered / Experimental CPT Codes
These seven codes are explicitly listed as "not covered for indications listed in the CPB." Submitting them for chemoresistance assay indications against Aetna plans generates a claim denial.
| Code | Type | Description | Reason |
|---|---|---|---|
| 0083U | CPT | Oncology, response to chemotherapy drugs using motility contrast tomography, fresh or frozen tissue | Not covered — experimental/investigational |
| 87230 | CPT | Toxin or antitoxin assay, tissue culture (e.g., Clostridium difficile toxin) | Not covered for indications listed in the CPB |
| 88104 | CPT | Cytopathology, fluids, washings or brushing, except cervical or vaginal; smears with interpretation | Not covered for indications listed in the CPB |
| 88305 | CPT | Level IV surgical pathology, gross and microscopic examination | Not covered for indications listed in the CPB |
| +88313 | CPT | Special stain including interpretation and report; Group II, all other (e.g., iron, trichrome) | Not covered for indications listed in the CPB |
| 88358 | CPT | Morphometric analysis; tumor (e.g., DNA ploidy) | Not covered for indications listed in the CPB |
| 89050 | CPT | Cell count, miscellaneous body fluids (e.g., cerebrospinal fluid, joint fluid), except blood | Not covered for indications listed in the CPB |
Key ICD-10-CM Diagnosis Codes
These diagnosis codes appear in CPB 0758. Their presence on a claim does not establish medical necessity or override the experimental designation for chemoresistance assays.
| Code | Description |
|---|---|
| C00.0–D49.9 | Neoplasms |
| Z51.11 | Encounter for antineoplastic chemotherapy and immunotherapy |
| Z51.12 | Encounter for antineoplastic chemotherapy and immunotherapy |
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