Modifier JW: Discarded Drug Amounts
The JW modifier reports the discarded part of a single-dose vial so Medicare pays for it. How to bill JW on two lines, when to use JZ, and the 2026 rules.
Modifier JW is a HCPCS Level II modifier that reports the amount of a drug or biological from a single-dose container that was discarded instead of given to the patient. CMS's descriptor is "Drug amount discarded/not administered to any patient." Medicare Part B pays for the discarded amount as well as the dose, up to the amount on the vial's label, but only when the waste is billed on its own line with JW (Pub. 100-04, ch. 17, §40).
Key takeaways
- Bill two lines with the same drug code: the administered units with no modifier, and the discarded units with JW.
- JW applies only to separately payable Part B drugs from single-dose containers or single-use packages, never multiple-dose vials.
- When nothing is discarded, the drug line takes modifier JZ instead. Since October 1, 2023, claims missing the right modifier may be returned.
- Record the discarded amount in the medical record.
- JW and JZ are drug-line modifiers. The administration code, such as an infusion, is billed without them.
Modifier JW · payment effect
With and without the modifier
96413 without JW · national office
$133.27
Chemo IV infusion
96413-JW · No change to the rate
$133.27
Reports the discarded amount from a single-dose drug container on its own line. The drug, not the fee schedule service, is paid.
When to use the JW modifier
Use JW when all of these are true:
- The drug is separately payable under Medicare Part B, such as a chemotherapy or biologic J-code given in the office alongside an infusion code like 96413.
- It comes from a single-dose container or single-use package under its FDA labeling. CMS publishes the list of codes that may need JW or JZ.
- Part of the container was discarded: the labeled amount minus the prescribed dose. CMS counts anything not part of the dose and not intended to have a therapeutic effect as discarded, even if it was drawn up.
How to bill it. CMS's example: a single-dose vial labeled 100 units, 95 given and 5 discarded. Line 1 is the drug code with 95 units and no modifier; line 2 is the same code with JW and 5 units. Both lines are paid. If two 50 mg vials are used to give 80 mg (1 mg billing unit), bill 80 units on line 1 and 20 units with JW on line 2 (JW/JZ FAQ, Q15).
Since January 1, 2025, a supplier that doesn't administer the drug but discards some during preparation also reports JW (ch. 17, §40).
When not to use the JW modifier
- Multiple-dose vials. Neither JW nor JZ applies.
- Overfill. Product beyond the labeled amount can't be billed at all (FAQ Q10).
- Drugs that aren't separately payable: packaged OPPS or ASC drugs, and drugs given in an FQHC or RHC.
- Vaccines paid under §1861(s)(10) of the Act (flu, pneumococcal, COVID-19).
- Incident-to supplies, including non-BLA skin substitutes. Since January 1, 2026, CMS pays those as supplies; discarded portions aren't billable under any modifier.
- Part B drugs under the Competitive Acquisition Program, where JW makes the claim unprocessable.
How JW affects payment
The JW line is paid like the dose line: at the drug's Part B payment rate (generally based on average sales price, not the physician fee schedule) times the discarded units. The administration service is paid separately from the fee schedule and isn't affected by JW or JZ.
JW and JZ data also feed the discarded drug refund. The Infrastructure Investment and Jobs Act requires manufacturers of refundable single-dose drugs to refund Medicare for certain discarded amounts, and CMS uses the modifiers to measure waste. CMS began using JW and JZ to calculate those refunds for dates of service from January 1, 2023 (FAQ, Policy).
JW vs JZ
| Modifier | CMS descriptor | Goes on | Units |
|---|---|---|---|
| JW | Drug amount discarded/not administered to any patient | A second line for the same drug code | Discarded units |
| JZ | Zero drug amount discarded/not administered to any patient | The only line for the drug | Administered units |
Every single-dose-container drug line now carries exactly one of the two: JW on the waste line when there is waste (the dose line has no modifier), or JZ on the dose line when there isn't.
FAQ
What is the difference between JW and JZ modifiers?
JW reports the discarded amount on its own line so Medicare pays for it. JZ attests that nothing was discarded and goes on the single line for the dose. A single-dose drug claim uses one or the other, never both on the same line.
What is modifier JW used for?
To bill the unused, discarded portion of a single-dose vial or single-use package of a separately payable Part B drug, so Medicare pays for it along with the administered dose.
For which payer are JW and JZ modifiers billed?
They are Medicare Part B requirements for traditional Medicare. Medicare Advantage plans and Medicaid programs set their own rules; many follow CMS, but check each payer's policy.
Does J1885 require a JZ or JW modifier?
It depends on the container. JW and JZ apply when the product used is labeled single-dose and is separately payable. Check the code on CMS's JW/JZ HCPCS list and the vial label: a multiple-dose vial takes neither.
How do I bill JW and JZ?
With waste: two lines for the drug code, administered units with no modifier and discarded units with JW. Without waste: one line with JZ and the administered units.
Keep reading
- Modifier JZ, the zero-waste attestation.
- Modifier GA when a drug or service may fail medical necessity.
- Codes on this page: 96413 96415 96365 96372
Sources: CMS Medicare Claims Processing Manual, Pub. 100-04, ch. 17, §40 (Rev. 13108, effective January 1, 2025); CMS Discarded Drugs and Biologicals: JW and JZ Modifier Policy FAQs. Verified October 6, 2026.
