Tumor In Vitro Chemosensitivity and Chemoresistance Assays - (0203) — MM 0203 | CIGNA Coverage Update

Cigna Healthcare modified MM 0203 for tumor in vitro chemosensitivity and chemoresistance assays, effective September 26, 2025. Every CPT code under this policy — including 0174U, 0248U, 0249U, 0525U, 0564T, 81535, and 81536 — carries an Experimental/Investigational/Unproven designation. Here's what your billing team needs to do.

Cigna Healthcare's Cigna in vitro chemosensitivity and chemoresistance assay coverage policy (MM 0203 Cigna system) covers seven codes, all classified as non-covered. If your oncology billing team submits any of these codes for Cigna members, expect a claim denial. This policy update, effective September 26, 2025, is a direct message to any practice still attempting reimbursement for tumor cell culture-based chemotherapy selection testing.

Quick-Reference Table

Cigna In Vitro Chemosensitivity Assay Coverage Criteria and Medical Necessity Requirements 2025

The core position in this Cigna coverage policy is unambiguous: Cigna does not consider tumor in vitro chemosensitivity and chemoresistance assays to meet medical necessity standards. The policy defines these assays as in vitro laboratory tests designed to help select chemotherapy based on how tumor cells respond outside the body. Cigna's position is that the clinical evidence does not support their use in guiding treatment decisions.

There are no tiered criteria here. There is no prior authorization pathway that unlocks coverage. There is no list of diagnoses or clinical scenarios where these tests become covered.

Every single code in MM 0203 sits in the Experimental/Investigational/Unproven bucket. That means Cigna will not reimburse these tests, full stop, regardless of the clinical rationale your ordering physician documents. If you're billing 81535 or 81536 for gynecologic oncology patients, or 0248U for brain tumor cases, or 0525U for the 11-drug spheroid cell culture panel — none of it is covered under this coverage policy.

Understanding this matters for prior authorization requests, too. Don't submit a prior auth for these codes expecting a different result. Cigna's experimental designation means the payer considers the scientific evidence insufficient to establish clinical utility. A prior authorization denial will follow any approval request for these services.

Cigna In Vitro Chemosensitivity Assay Exclusions and Non-Covered Indications

All seven codes in MM 0203 are classified as Experimental/Investigational/Unproven. This isn't a partial restriction — it's a blanket exclusion across every assay type the policy addresses.

The tests covered by this designation include mass spectrometric protein target analysis (CPT 0174U), 3D spheroid cell culture drug panels for brain tumors (CPT 0248U), phosphoprotein analysis for breast oncology (CPT 0249U), the 11-drug spheroid panel for solid tumors (CPT 0525U), cancer stem cell cytotoxicity assays (CPT 0564T), and live tumor cell culture with DAPI staining for gynecologic oncology (CPT 81535 and 81536).

The reasoning behind an Experimental/Investigational/Unproven designation is important for your billing conversations. It means Cigna reviewed the clinical literature and found insufficient peer-reviewed evidence that these assays improve patient outcomes compared to standard oncology treatment selection methods. This is a different designation than "non-covered for administrative reasons" — it carries a specific evidentiary meaning that affects how you handle appeals.

Appeals based on medical necessity documentation alone will not succeed here. Cigna's experimental designation requires evidence at the payer-policy level, not the patient-specific level. If you plan to appeal a denial for any of these codes, loop in your compliance officer and consider whether you have access to published clinical evidence or an institutional review board-approved protocol — those are the only pathways that sometimes move experimental designations.

Coverage Indications at a Glance

Cigna In Vitro Chemosensitivity and Chemoresistance Assay Billing Guidelines and Action Items 2025

The effective date is September 26, 2025. The actions below are time-sensitive if your team bills any of these codes.

CPT, HCPCS, and ICD-10 Codes for In Vitro Chemosensitivity and Chemoresistance Assays Under MM 0203

Covered CPT Codes

There are no covered CPT codes under MM 0203. Cigna considers all seven codes in this policy Experimental/Investigational/Unproven.

Not Covered / Experimental Codes

Key ICD-10-CM Diagnosis Codes

MM 0203 does not list specific ICD-10-CM diagnosis codes. The Experimental/Investigational/Unproven designation applies regardless of diagnosis code.

The Real Issue with MM 0203

This policy change matters beyond the denial risk. Seven codes, all non-covered — that's a clear signal that Cigna has reviewed the clinical evidence landscape for in vitro chemosensitivity testing and is not moving toward coverage anytime soon.

The U-codes and Category III codes in this list (0174U, 0248U, 0249U, 0525U, 0564T) are newer additions to the CPT code set. Some billing teams assume newer technology codes are working their way toward coverage as evidence accumulates. Cigna's position in MM 0203 pushes back against that assumption for these specific assays.

The practical question for your practice: are you ordering these tests with the expectation of billing them to Cigna? If so, you're generating uncollectable revenue and patient financial exposure. Recalibrate your test ordering workflows now, before the September 26, 2025 effective date locks in the denial pattern.