Extracorporeal Immunoadsorption (Prosorba column) — CPB 0355 | AETNA Coverage Update

TL;DR: Aetna, a CVS Health company, modified CPB 0355 covering extracorporeal immunoadsorption (ECI) using the Prosorba column, effective September 26, 2025. If your team bills CPT 36516 for Aetna members, here's what changed and what to do before claims start denying.

The updated Aetna extracorporeal immunoadsorption coverage policy defines six specific indications where ECI is medically necessary — with precise clinical thresholds that determine whether a claim flies or gets denied on medical necessity grounds. This policy governs CPT 36516 (therapeutic apheresis with extracorporeal immunoadsorption) along with related HCPCS drug codes J7500, J7501, J7502, J7515, and J7516. If your practice treats patients with rheumatoid arthritis, ITP, pemphigus vulgaris, or systemic lupus erythematosus and bills Aetna, this update directly affects your reimbursement.

Quick-Reference Table

Aetna Extracorporeal Immunoadsorption Coverage Criteria and Medical Necessity Requirements 2025

The CPB 0355 Aetna system policy defines ECI as medically necessary under six specific clinical scenarios. Get these wrong on a claim and you're looking at a medical necessity denial — not a coding denial. Those are harder to appeal and slower to resolve.

Here's the core structure: each covered indication has a threshold requirement. Meeting the diagnosis alone is not enough. Your documentation needs to show the clinical criteria are satisfied at the time of treatment.

Indication 1 — Hemolytic Uremic Syndrome (HUS)
Covered when there is clinical evidence of serious bleeding with a platelet count below 50,000, or the potential for serious bleeding with a platelet count below 20,000. The ICD-10 codes D59.31 through D59.39 map to this indication. The platelet threshold must be documented in the medical record.

Indication 2 — Idiopathic Thrombocytopenic Purpura (ITP)
Same platelet thresholds as HUS — serious bleeding with platelets below 50,000, or bleeding risk with platelets below 20,000. ICD-10 D69.3 is your primary diagnosis code here. Document the platelet count explicitly. Without it, prior authorization reviewers will flag it and your claim faces a denial.

Indication 3 — Systemic Lupus Erythematosus (SLE)
ECI is covered only as a last resort for life-threatening SLE after conventional therapy has failed to prevent clinical deterioration. This is one of the tighter criteria in the policy. "Life-threatening" and "failed conventional therapy" both need to be supported in the documentation. A clinical note that says treatment was "not fully effective" won't cut it.

Indication 4 — Rheumatoid Arthritis (RA)
Covered for moderate-to-severe RA to reduce signs and symptoms when other treatments have failed. The policy specifically calls out non-steroidal anti-inflammatory drugs and methotrexate as examples of prior failed therapies. Your documentation needs a clear treatment failure history. This is the indication most likely to generate prior authorization scrutiny — RA is high-volume and payers watch it.

Indication 5 — Myasthenic Crisis
Covered when conventional therapy has failed. The policy names intravenous immunoglobulin (IVIG) and plasma exchange as the standard first-line treatments that must have been tried first. ICD-10 G70.01 applies here. Document the failed conventional treatments with dates and outcomes before billing CPT 36516 under this indication.

Indication 6 — Pemphigus Vulgaris
Covered when the condition is resistant to standard therapy. The policy specifically names dapsone, corticosteroids, and immunosuppressants — including azathioprine (J7500, J7501) and cyclosporine (J7502, J7515, J7516) — as the treatments that must have failed. ICD-10 codes L10.0 through L10.7 cover the pemphigus spectrum. If your patient is on azathioprine or cyclosporine, those HCPCS codes are listed in the policy as related codes — not separately billable for ECI itself, but relevant to establishing prior treatment failure.

The real issue with all six indications: this is a step-therapy and last-resort heavy policy. Every indication except HUS and ITP requires documented failure of prior treatment. Your clinical documentation is your defense against a claim denial.

Aetna Extracorporeal Immunoadsorption Exclusions and Non-Covered Indications

The policy does not provide an explicit experimental or non-covered list in the sections available, but the coverage structure itself creates clear exclusions by omission. ECI is not medically necessary under CPB 0355 for any indication not listed in the six covered criteria.

Conditions that appear in the ICD-10 code table but are not covered indications — such as heart failure (I50.x), asthma (J45.x), acute hepatitis B (B16.x), interstitial lung disease (J84.x), and neuromyelitis optica (G36.0) — should be treated as non-covered for ECI under this policy. Those codes appear in the policy's broader ICD-10 list, but they do not map to any of the six covered indications. Billing CPT 36516 with those diagnoses as the primary indication will result in a medical necessity denial.

If you have patients with those diagnoses who are receiving ECI, talk to your compliance officer before billing. The mismatch between the ICD-10 codes in the policy table and the covered indications is genuinely confusing, and you do not want to find out after the fact that you built a billing pattern on an unsupported interpretation.

Coverage Indications at a Glance

Aetna Extracorporeal Immunoadsorption Billing Guidelines and Action Items 2025

This policy became effective September 26, 2025. If your team hasn't audited CPT 36516 claims submitted after that date, do it now.

CPT, HCPCS, and ICD-10 Codes for Extracorporeal Immunoadsorption Under CPB 0355

Covered CPT Codes (When Selection Criteria Are Met)

Key ICD-10-CM Diagnosis Codes

Note: ICD-10 codes beyond the six covered indications appear in the policy's broader code table. Billing CPT 36516 with those diagnosis codes as the primary indication is not supported by the CPB 0355 medical necessity criteria. Review with your compliance officer before using them as the basis for ECI claims.