TL;DR: The Centers for Medicare & Medicaid Services modified NCD 148 governing lymphocyte immune globulin, anti-thymocyte globulin (equine) coverage, effective March 7, 2026. Here's what billing teams need to know.
The CMS anti-thymocyte globulin (equine) coverage policy under NCD 148 Medicare is narrower than many transplant billing teams assume. This policy covers exactly one FDA-approved preparation—lymphocyte immune globulin, anti-thymocyte globulin (equine)—and only for a specific, documented indication: managing allograft rejection episodes in renal transplantation. The policy does not list specific HCPCS or CPT codes, which creates real documentation risk if your team hasn't built the right clinical justification into your billing workflow before the effective date of March 7, 2026.
Quick-Reference Table
| Field | Detail |
|---|---|
| Payer | CMS (Centers for Medicare & Medicaid Services) |
| Policy | Lymphocyte Immune Globulin, Anti-Thymocyte Globulin (Equine) |
| Policy Code | NCD 148 |
| Change Type | Modified |
| Effective Date | 2026-03-07 |
| Impact Level | Medium — narrow but firm coverage criteria with real claim denial risk for off-label use |
| Specialties Affected | Nephrology, Transplant Surgery, Transplant Medicine, Hospital Pharmacy, Inpatient/Outpatient Facility Billing |
| Key Action | Confirm all anti-thymocyte globulin (equine) claims document renal allograft rejection as the indication before March 7, 2026 |
CMS Anti-Thymocyte Globulin Coverage Criteria and Medical Necessity Requirements 2026
The CMS anti-thymocyte globulin (equine) coverage policy is built around one core rule: Medicare covers this drug when used for the management of allograft rejection episodes in renal transplantation. That's it. Not prophylaxis. Not aplastic anemia. Not off-label transplant indications in other organs. Renal allograft rejection.
Medical necessity under NCD 148 requires the drug to be used as an adjunct to conventional immunosuppressive therapy—steroids and anti-metabolic drugs. The policy is explicit that lymphocyte immune globulin preparations are not replacements for conventional immunosuppressive agents. They supplement them, or serve as an alternative when conventional agents would need to be used at elevated or accelerated doses.
This is a critical documentation point for medical necessity. If your clinical team is using anti-thymocyte globulin (equine) because a patient can't tolerate higher steroid doses, document that reasoning specifically. "Alternative to accelerated conventional immunosuppression" is language the policy itself uses—your medical record should reflect it.
The policy also opens a forward-looking door: other FDA-approved lymphocyte globulin preparations, for the same renal transplant rejection indication, may be covered under Medicare as they receive FDA approval. That's not hypothetical coverage today—it's a framework for future coverage. Don't bill a non-equine preparation under this NCD without confirming FDA approval status for the specific indication.
Prior authorization requirements are not explicitly outlined in NCD 148 itself. However, your Medicare Administrative Contractor may apply additional local coverage requirements. Check with your MAC before assuming national coverage alone is sufficient for reimbursement. Regional variation exists, and a prior authorization requirement at the MAC level will still result in a claim denial if you skip it.
CMS Anti-Thymocyte Globulin Exclusions and Non-Covered Indications
The policy draws a clear line at the FDA approval boundary. Lymphocyte immune globulin preparations of equine, lapine, and murine origin—other than the one FDA-approved equine preparation—are described as "currently under investigation." Under NCD 148, these investigational preparations are not covered.
This is not a gray area. CMS calls out lapine and murine origin preparations explicitly as under investigation. Billing any of these under the same coverage rationale as the FDA-approved equine preparation is incorrect and exposes you to recoupment risk.
The policy also doesn't cover this drug for non-renal transplant indications. Aplastic anemia treatment with anti-thymocyte globulin is a legitimate clinical use—but it's not what this NCD covers. If your facility bills for aplastic anemia treatment, you need a separate coverage basis. NCD 148 does not provide it.
Coverage Indications at a Glance
| Indication | Status | Relevant Codes | Notes |
|---|---|---|---|
| Renal allograft rejection management in renal transplantation | Covered | No specific codes listed in NCD 148 | Must be adjunctive to conventional immunosuppression; document this explicitly |
| Use as replacement (not supplement) for conventional immunosuppressive drugs | Not Covered | — | Policy states this drug supplements, not replaces, standard therapy |
| Investigational preparations (lapine, murine origin) | Not Covered | — | Under investigation; not FDA-approved for this indication |
| Non-renal transplant indications (e.g., aplastic anemia) | Not Covered under NCD 148 | — | Requires separate coverage determination; NCD 148 does not apply |
| Future FDA-approved lymphocyte globulin preparations for renal allograft rejection | Potentially Covered | — | CMS language allows for coverage if/when FDA approval is granted for this indication |
CMS Anti-Thymocyte Globulin Billing Guidelines and Action Items 2026
Anti-thymocyte globulin (equine) billing under NCD 148 requires more documentation discipline than most drug claims. Here's what your team should do before and after March 7, 2026.
| # | Action Item |
|---|---|
| 1 | Audit your current claims for this drug before March 7, 2026. Pull any pending or recently submitted claims for anti-thymocyte globulin (equine) and confirm the documented indication is renal allograft rejection. Any claim without this documented indication is a claim denial waiting to happen. |
| 2 | Check with your MAC for local coverage requirements. NCD 148 sets the national floor. Your Medicare Administrative Contractor may have a local coverage determination that adds prior authorization, documentation, or step therapy requirements on top. Don't assume the NCD is the complete picture—call or check your MAC's website directly. |
| 3 | Update your clinical documentation templates to reflect adjunctive use. Your medical record needs to show that anti-thymocyte globulin (equine) is being used alongside conventional immunosuppressive therapy, or as an alternative to escalating conventional therapy. A bare diagnosis code for transplant rejection is not enough. The reasoning for using this drug—specifically, why it's appropriate instead of or alongside steroids and anti-metabolic drugs—must be in the chart. |
| 4 | Stop billing investigational preparations under this NCD. If your facility uses any lapine or murine-origin lymphocyte globulin preparations, do not bill those under NCD 148. They do not have FDA approval for this indication. File those claims only if you have a separate, valid coverage basis—and loop in your compliance officer before you do. |
| 5 | Flag the "future FDA-approved preparations" language for your pharmacy and billing teams. The policy says new FDA-approved lymphocyte globulin preparations may be covered for renal allograft rejection in the future. Set a process now: when a new preparation gets FDA approval for this indication, your team should verify Medicare coverage before billing. Don't assume it's covered because the NCD has that forward-looking language—verify through your MAC. |
| 6 | Confirm your reimbursement pathway for this drug in your setting. Anti-thymocyte globulin (equine) is a high-cost biologic. Whether you're billing for inpatient administration (bundled into DRG) or outpatient/Part B (separately reimbursable), the pathway matters for how you document and submit. If you're not sure how your facility handles reimbursement for this drug, resolve that with your billing team before the effective date. |
If you're managing a mixed transplant program with multiple immunosuppressive agents and you're unsure how your documentation holds up under NCD 148, talk to your compliance officer before March 7, 2026. The financial exposure on a high-cost biologic claim is not a situation where you want to find out after the fact.
| 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 Anti-Thymocyte Globulin (Equine) Under NCD 148
NCD 148 as modified does not include CPT, HCPCS Level II, or ICD-10-CM codes in the policy document.
This is not unusual for older NCDs that predate the modern HCPCS coding structure for biologics—but it does create a real billing challenge. Without code-level guidance in the NCD itself, your team cannot rely on the policy document alone for code selection.
What to Do When Codes Aren't Listed
Contact your MAC directly and ask which codes they expect for anti-thymocyte globulin (equine) claims under NCD 148. Your MAC's claims processing instructions—referenced in the policy's Cross Reference section—are the operative guide for code selection. Pull those instructions and make sure your charge capture matches what your MAC expects.
Do not assume code coverage from this NCD alone. The absence of specific codes in the policy means MAC-level guidance is required to bill correctly.
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