HCPCS code J7520 – Oral sirolimus

Key takeaways

HCPCS code J7520 is sirolimus, oral, 1 mg, so you bill one unit for every milligram of tablets or oral solution dispensed.

Medicare pays it under Part B only after a Medicare-covered organ transplant, with Part A in place on the transplant date.

A transplant diagnosis such as Z94.0, T86.11 or Z48.22 has to be on the claim, or the drug falls outside the benefit.

Pharmacies and suppliers bill the DME MAC, and the October 2026 Medicare payment limit is $0.609 per 1 mg unit.

Cyclosporine never belongs on J7520. Oral cyclosporine is J7502 or J7515, and the injection is J7516.

HCPCS code J7520 covers oral sirolimus, one unit per milligram

HCPCS code J7520 is the Level II code for sirolimus, oral, 1 mg. Medicare reimburses it through the immunosuppressive drug benefit, which CMS limits to patients with a Medicare-covered organ transplant in Policy Article A52474. Sirolimus is an mTOR inhibitor, sold first as Rapamune and now mostly as generic tablets and oral solution.

J7520 describes oral sirolimus only. The injectable and topical forms of the drug have no place on it.

The payment limit comes from the CMS Medicare Part B payment limit file effective October 1, 2026. It changes every quarter, so check the current file before you quote a figure to a patient.

Count units in milligrams, whatever the tablet strength

Units on J7520 follow the dose in milligrams, never the tablet count. A bottle of 1 mg tablets gives one unit per tablet, which makes counting tablets look safe. Switch the patient to 2 mg tablets and the count doubles.

Here’s how three common dispenses work out:

• 2 mg daily for 90 days. 90 tablets of 2 mg is 180 mg, so you bill 180 units.
• 0.5 mg tablets, 60 dispensed. That’s 30 mg in total, so you bill 30 units.
• Oral solution, one 60 mL bottle at 1 mg/mL. The bottle holds 60 mg, so you bill 60 units.

Run the first example through the October 2026 limit and the allowed amount is 180 × $0.609, or $109.62. Medicare pays 80% of that after the Part B deductible, and the patient owes $21.92 in coinsurance.

Keep each dispense to a 90-day supply or less. The DME MAC coverage policy L33824 moved the limit from 30 to 90 days for dates of service from January 1, 2025.

Part B only pays for J7520 after a Medicare-covered transplant

Policy Article A52474 sets five criteria, and the claim fails if any one of them is missing:

1. The patient had a qualifying transplant. That means kidney, heart, liver, lung, heart-lung, bone marrow or stem cell, or intestine.
2. A pancreas transplant counts with a kidney transplant, alone under strict type 1 diabetes criteria, or as islet cells in an NIH-sponsored trial.
3. Medicare paid for the transplant. A Medicare Advantage plan paying for it still counts.
4. The patient had Part A on the date of the transplant.
5. The patient has Part B on the date the drug is dispensed, and the drug arrives after discharge.

Kidney recipients whose Medicare came from end-stage renal disease alone lose it 36 months after a successful transplant. Since January 1, 2023, they can keep paying for Part B only to cover these drugs. CMS calls this the Part B immunosuppressive drug benefit, or Part B-ID.

Sirolimus is FDA-approved to prevent rejection after a kidney transplant in patients aged 13 and over. Its label also covers lymphangioleiomyomatosis (LAM), a rare lung disease. A LAM patient with no transplant has no claim under this benefit, so check their Part D plan instead.

Off-label transplant use is no longer an automatic denial. Since April 2025, L33824 also covers FDA-approved drugs the DME MAC judges reasonable and necessary against rejection. Keep the prescriber’s rationale on file, because that judgment is made claim by claim.

Transplant ICD-10 codes carry the medical necessity

A52474 accepts 64 ICD-10-CM diagnostic codes, and every other diagnosis is treated as not supporting the drug. They fall into three families: Z94 transplant status, T86 transplant complications and Z48.2 aftercare. Sirolimus is labeled for kidney transplants, so these are the codes you’ll reach for first:

Code what the prescriber documented. If the note says the graft is stable, Z94.0 is the right code, and a failing graft takes T86.12. Reaching for T86.11 to make a claim look stronger only invites a review.

How a J7520 claim moves from prescription to payment

The transplant practice writes the order, but the pharmacy or supplier usually sends the Medicare claim. Both sides have to hold the same facts. The checks below are the ones that decide whether the claim pays.

1. The order. The prescriber sends a standard written order with the drug, dose and quantity. The supplier also needs the transplant date in writing, so put it in the order or the cover note.
2. The dispense. A retail pharmacy can bill the DME MAC in NCPDP format, using the NDC. A supplier billing on an 837P uses J7520 with units in milligrams.
3. The supply fee. Q0510 pays once for the first prescription after a transplant. After that, Q0511 covers the first drug in each 30- or 90-day period and Q0512 each additional drug.
4. The modifiers. Add KX only when you hold the transplant date and proof of Part A at transplant. Add GY when any coverage criterion fails.
5. The remit. A CO-107 denial means Medicare couldn’t find a covered transplant, which is the cue to check KX and the transplant records.

KX is optional, according to chapter 17 of the Medicare Claims Processing Manual. It matters most when Medicare has no record of the transplant claim, for example after a Medicare Advantage-paid transplant. Supply fees go on the same claim as the drug and are denied with it.

Hospital discharges need one more check. A mail-order supplier may ship up to two days before discharge, but the date of service then becomes the discharge date. Ship earlier, or bill before discharge, and the claim rejects, because the hospital owns inpatient drugs.

NDC reporting uses UN for tablets and ML for solution

Commercial plans and Medicaid often want the NDC alongside J7520 on an 837P or CMS-1500. Many commercial plans skip J7520 altogether and run oral sirolimus through the pharmacy benefit, where the NDC is the only drug identifier.

When a payer does want the NDC on a professional claim, the format is fixed:

• Use the 11-digit NDC in 5-4-2 format, padding with a leading zero where the package shows fewer digits.
• Put the N4 qualifier directly in front of it, with no spaces.
• Report tablets with the UN unit of measure and the tablet count.
• Report oral solution with ML and the volume dispensed.

A worked example: Zydus sirolimus 1 mg, 100 tablets, carries package NDC 65841-772-01. In 11-digit form that’s 65841077201, reported as N465841077201 UN100. The HCPCS line still reads J7520 × 100 units.

Take the NDC from the package you dispensed, not from a saved template. Generic labelers change often, and a stale NDC is one of the quickest ways to get a drug line rejected.

Don’t mix up J7520 with the other J75xx codes

The immunosuppressive drug codes sit in the J7500 to J7599 range, and several share drugs, routes or unit sizes. These are the neighbors that cause the most trouble, with payment limits from the same October 2026 file:

Two mix-ups come up again and again. The first is billing cyclosporine on J7520. Cyclosporine has its own codes (J7502, J7515, J7516). No 10 mg cyclosporine code exists.

The second is treating sirolimus and everolimus as interchangeable. Both are mTOR inhibitors, but everolimus has its own code, J7527, with a 0.25 mg unit. Swap them and both the drug and the unit count are wrong.

Before you submit: A J7520 checklist

• The drug on the label is sirolimus, and the route is oral.
• Units equal total milligrams dispensed, checked against the tablet strength.
• The supply is 90 days or less.
• The transplant date and organ are documented, along with proof of Part A on that date.
• Part B is active on the date of service, or the patient is enrolled in Part B-ID.
• A Z94, T86 or Z48.2 diagnosis matches the prescriber’s note.
• KX or GY is applied correctly, and Q0510, Q0511 or Q0512 sits on the same claim.
• The date of service is the delivery date, or the discharge date for an early mail-order shipment.
• The NDC matches the package dispensed when the payer asks for it.

Common mistakes that get J7520 claims denied

• Counting tablets instead of milligrams. It works for 1 mg tablets and fails the moment the strength changes.
• Billing a non-transplant use to Part B. LAM and other indications belong with the patient’s Part D plan.
• Leaving out the transplant date. Without it the supplier can’t support KX, and a Medicare Advantage-era transplant looks uncovered.
• Delivering to the hospital ward. Inpatient drugs are the facility’s responsibility, so a dispense before discharge rejects.
• Double-claiming Q0510. It pays once per transplant, to one supplier, even after a multi-organ transplant.
• Using a stale fee schedule. The payment limit moves each quarter, so an old figure leaves money on the table or creates an overpayment.

Three edge cases billing teams ask about

The patient’s ESRD Medicare is ending. What happens to their sirolimus? Coverage stops 36 months after a successful kidney transplant unless they enroll in Part B-ID. Flag the date three months ahead, so the switch happens before the next refill.

The patient is in a Medicare Advantage plan. The plan pays, not the DME MAC, and its own pharmacy and authorization rules apply. If they later return to Original Medicare, the plan’s payment for the transplant still meets the coverage criterion.

The prescriber wants to bill J7520 directly. The LCD allows a treating practitioner to bill only when they meet enrollment and state rules for dispensing. If they don’t, the dispensing pharmacy bills.

How Pabau keeps transplant prescribing records claim-ready

The facts a J7520 claim depends on start in the transplant practice. When the transplant date, the organ, Part A status and the dose sit in different notes, the pharmacy calls and waits.

Pabau, the practice management and EHR platform we build, keeps those details on one patient record. The transplant history, prescriptions and diagnoses sit side by side, so your team can answer a supplier’s request for the transplant date in one look.

Practices can also switch on a patient portal where patients see their prescriptions and request refills, which keeps their supply on schedule.

When your practice bills a plan itself, Pabau’s claims management software sends CMS-1500 and 837P claims through Claim.MD. It checks eligibility first, then posts the remittance when it comes back.

Keep transplant drug claims moving

Pabau keeps the transplant date, diagnosis and prescription on one patient record, so pharmacies get what they need for a J7520 claim. Your team stops chasing notes.

Book a demo

Conclusion

J7520 comes down to three facts. It is oral sirolimus, billed a milligram per unit, for Medicare-covered transplant patients. Each one maps to a denial when it’s missing.

If you change one habit, make it sending the transplant date with every new sirolimus order. It protects the KX attestation, settles the coverage question and saves the pharmacy a phone call. Count milligrams, never tablets, and recheck the payment limit each quarter.

Book a demo to see how Pabau keeps transplant histories, prescriptions and claims on one record for your practice.

Continue your research

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