JW tells Medicare how much drug you threw away from a single-dose vial or single-use package. It goes on its own claim line. Line 1 has the drug code, no modifier, and the units you gave. Line 2 has the same code, JW, and the units you discarded. Medicare pays both lines, up to the amount on the vial label.
If nothing was thrown away, do not use JW. Bill one line with the JZ modifier instead. Medicare has required JW since January 1, 2017, and JZ since July 1, 2023. Since October 1, 2023, Medicare can send back a single-dose drug claim that is missing the right modifier.
Medicare pays for drug you had to throw away from a single-dose vial, as long as it is not more than the amount on the label. Since 2023, drug makers also owe Medicare a refund for some of that discarded drug, under section 90004 of the Infrastructure Investment and Jobs Act. CMS counts the discarded units from your JW lines. That is why JW is required on every claim with waste, and why CMS added JZ to confirm when there was none.
Doses based on weight or body size usually leave drug in the last vial, so they usually need JW. Flat doses that use whole vials, such as Keytruda 200 mg from two 100 mg vials, usually need JZ. Check the actual dose every time. The same drug can need JW one visit and JZ the next.
The JW and JZ rules are Medicare Part B rules. They cover drugs that Medicare pays for separately. This table shows each setting, from the CMS FAQ unless noted.
| Setting | JW or JZ required? | Rule |
|---|---|---|
| Physician office | Yes | Almost every drug given incident to a physician service is paid separately, so every single-dose drug needs JW or JZ. |
| Hospital outpatient (OPPS) | Only for some drugs | Required for drugs with status indicator G (pass-through) or K (paid separately). Not used for status indicator N (packaged). |
| Ambulatory surgery center | Only for some drugs | Required for payment indicator K2. Not used for N1 (packaged). |
| Critical access hospital | Yes | Drugs are paid separately in this setting, so the rule applies. |
| 340B hospitals | Yes | 340B covered entities still report JW and JZ (Noridian). |
| Dialysis (ESRD) facility | Only for some drugs | Only for drugs that are not renal dialysis drugs. Report JW or JZ with the AY modifier. |
| Pharmacy or supplier that does not give the drug | Yes | Report JZ. Since January 1, 2025, report JW for drug thrown away while preparing it. |
| Rural health clinic or FQHC | No | Drugs are part of the visit rate, not paid separately. |
| Hospital inpatient (IPPS) | No | Also not on outpatient drugs moved onto the inpatient claim by the 3-day or 1-day window. |
| Medicare Advantage, Medicaid, commercial plans | Plan rules | The CMS FAQ covers Medicare Part B claims. Other plans set their own rules. Check the plan’s billing policy before you assume it follows Medicare. |
Amounts are Medicare-allowed amounts for October–December 2026: the drug at the Medicare payment limit and the infusion at the national physician-office rate. Medicare pays 80%. The patient or a secondary plan owes 20%.
| Mistake | What happens | Fix |
|---|---|---|
| No JW and no JZ on a single-dose drug | Since October 1, 2023, Medicare can return the claim as unprocessable. | Add the JW line if drug was thrown away, or JZ if none was. Resubmit. |
| JW line with no matching line | Medicare’s system needs every JW line paired with a line for the same code with no modifier. Without it, the claim comes back. | Add the line for the units given, with no modifier. |
| JW and JZ on the same line | The two mean opposite things. | Waste: two lines, JW on the waste line only. No waste: one line with JZ. |
| JW on a multiple-dose vial | CMS says the modifiers are not appropriate for multiple-dose containers. | Remove JW. Bill the units given with no waste modifier. |
| JW used for overfill | Overfill is drug beyond the label amount. Medicare does not pay for it. | Remove it. The two lines should add up to the labeled amount in the vials opened. |
| Part units on a line | CMS does not use part units. | Round the dose up to a whole unit. Put the rest of the vial on the JW line. |
| Biosimilar billed under the reference drug’s code | The modifier is right, but the drug code is wrong. | Use the biosimilar’s own code on both lines. Example: Riabni (rituximab-arrx) is Q5123, not J9312. |
JW reports drug you threw away from a single-dose vial. It goes on its own line. JZ says nothing was thrown away. It goes on the one line for the units given. Never put both on the same line.
Medicare has required JW on single-dose drug claims with waste since January 1, 2017. JZ became required July 1, 2023 (CMS Change Request 13056, Transmittal R12067CP, MLN Matters MM13056). Since October 1, 2023, Medicare can return claims that leave both modifiers off.
Read the FDA-approved label. “Single-dose” or “single-use” means the rule applies. CMS also posts a list of drug codes that only come in single-dose containers on its ASP billing resources page and updates it about twice a year. CMS says the list is not complete, so a drug that is missing from it can still need JW or JZ.
No. Neither JW nor JZ is used for a drug from a multiple-dose vial, even if drug is left in it.
Do not use JW. CMS does not use part units, so bill one full unit with JZ.
No. Overfill is any drug beyond the amount on the label. Medicare has barred billing for it since January 1, 2011, and JW must not be used for it.
A claim line holds at most 9,999 units, so the dose is split across lines. CMS puts JZ on each full 9,999-unit line, bills the remainder with no modifier, and puts the discarded units on a JW line. CMS’s own example: 49,000 units given and 1,000 discarded bills as four JZ lines of 9,999, one line of 9,004 with no modifier, and one JW line of 1,000. This is the only case where one claim has both modifiers, each on different lines.
Write the amount discarded in the patient’s medical record. CMS does not set a format or say who must record it. A software calculation is fine as long as the amount is accurate. Ask your Medicare contractor if it has local rules.
Yes, the same way. Use the biosimilar’s own code on both lines. For example, Riabni (rituximab-arrx) bills as Q5123, not as Rituxan’s J9312.
Yes. Noridian, a Medicare contractor, says 340B covered entities must still report JW and JZ.
How we handle sources that disagree is described in the Methodology.