Modifier JZ: Zero Drug Amount Discarded
Modifier JZ attests that nothing was discarded from a single-dose vial or package, so no JW line applies. It has been required on Medicare Part B drug claims for dates of service from July 1, 2023, and a claim without the right modifier can be returned unprocessed.
Written by Salman Saeed, CEO and Co-Founder · Reviewed by a Certified Medical Coder · Last reviewed October 2026In short: put JZ on the one drug line when every unit was used. Use JW on a second line when some was discarded. When the dose is smaller than one billing unit, bill the whole unit with JZ and never JW.
What Does Modifier JZ Mean?
Modifier JZ is a HCPCS Level II modifier listed in the October 2026 CMS file as "Zero drug amount discarded/not administered to any patient," added January 1, 2023. It attests that no amount of a single-dose drug was discarded.
Chapter 17, section 40, requires it on dates of service from July 1, 2023 for separately payable Part B drugs from single-dose containers or single-use packages. The line carries the drug code, JZ and the units administered, on one line. Where JW would be required if something had been wasted, JZ is required when nothing was.
The count of vials does not change this. CMS gives two 50 mg vials used for a 100 mg dose with one unit per mg: one line, 100 units, JZ.
When Did JZ Become Required?
| Date | What changed | Source |
|---|---|---|
| January 1, 2023 | JZ became available, and CMS began using JW and JZ data to calculate discarded drug refunds. | FAQ 12 and policy summary |
| July 1, 2023 | JZ required on single-dose container drug claims with no discarded amount. | Chapter 17, section 40 |
| October 1, 2023 | Claims without the right modifier may be returned as unprocessable. | FAQ 5 and 13 |
| Calendar year 2024 | Suppliers that dispense but do not administer must report JZ. | Chapter 17, section 40 |
| January 1, 2025 | Those suppliers report JW if they discard some during preparation, otherwise JZ. | Chapter 17, section 40 |
| January 1, 2026 | JZ is not appropriate for an entire non-BLA skin substitute administered. | FAQ 9 |
What If the Dose Is Smaller Than One Billing Unit?
Bill the whole billing unit with JZ. CMS does not use fractional billing units, and a JW line for the leftover would double pay it. The manual says to use JZ for dates of service from July 1, 2023 when the billing unit is equal to or greater than the actual dose plus the discarded amount.
One billing unit is 10 mg in a single-use vial. A 7 mg dose is given and 3 mg remains.
The JZ line does not have to account for whole vials, and the JW policy does not require whole vials either.
How Is JZ Billed When the Dose Runs Past 9,999 Units?
A claim line holds at most 9,999 units, so a large dose needs several lines. With no waste, every line takes JZ. CMS gives a 22,000 unit example: 9,999 units with JZ, 9,999 units with JZ and 2,002 units with JZ.
With waste, the layout changes. For 49,000 units given and 1,000 discarded from 50,000, CMS bills four lines of 9,999 units with JZ, one line of 9,004 units with no modifier, and one JW line for 1,000 units. The no-modifier line is what lets the JW line pass the claim edit.
When Is JZ Not Used?
- Drugs that are not separately payable, such as OPPS drugs with status indicator N and ASC drugs with payment indicator N1
- Drugs administered in a rural health clinic or FQHC, because they are paid in the all-inclusive or prospective rate
- Hospital inpatient claims under IPPS, including outpatient drugs pulled into the 3-day or 1-day payment window
- Multiple-dose containers
- Influenza, pneumococcal and COVID-19 vaccines under section 1861(s)(10), because mass immunizers use roster billing
- Incident-to supplies, and from 2026 an entire non-BLA skin substitute
The requirement is independent of revenue code. A hospital reports the revenue code that fits the service, not revenue code 636 just to trigger the modifier.
How Does Modifier JZ Read on the Form and on the Remittance?
JZ goes on the drug line in item 24D or FL 44 when no drug was discarded.
A CO-16 with MA130 means a new claim is needed. A CO-4 means the modifier did not fit. Compare the drug code and the modifier.
A single-dose drug line with no JZ returns CO-16 with MA130 for $0.00.
Which Denials Follow a Missing JZ?
| Code | X12 description | Usual cause here |
|---|---|---|
| CO-16 | Claim/service lacks information or has submission/billing error(s). | JZ missing on a single-dose drug line with no waste. |
| RARC MA130 | Your claim contains incomplete and/or invalid information, and no appeal rights are afforded because the claim is unprocessable. | The claim was returned. Correct it and send a new claim. |
| CO-4 | The procedure code is inconsistent with the modifier used. | JZ on a multi-dose, packaged or non-drug line. |
Compare modifier JW for the second line when something was wasted. Our billing and coding audits check each drug line for the right modifier. If these denials keep coming back, our denial management team can work them.
Related Codes
- Medicare Claims Processing Manual, chapter 17, Drugs and Biologicals, section 40 · CMS
- Discarded Drugs and Biologicals: JW Modifier and JZ Modifier Policy Frequently Asked Questions · CMS
- HCPCS Level II quarterly update, October 2026 alpha-numeric file · CMS
- X12 Claim Adjustment Reason Codes and group codes · X12
- X12 Remittance Advice Remark Codes · X12
- Medicare Claims Processing Manual, chapter 26 (CMS-1500 items) · CMS
- Medicare Claims Processing Manual, chapter 22, sections 60.1 to 60.3 (group codes, CARC, RARC on the remittance) · CMS
We check every rule, code and deadline against the official source. See our editorial policy.
Common Questions
Straight answers from the team that does the work.
Ask a billing lead directly. A 20-minute call, Monday to Friday, 9am to 5pm Eastern.
01When is modifier JZ required instead of JW?
JZ is required when a separately payable Part B drug comes from a single-dose container or single-use package and nothing was discarded. JW is for the discarded part. The manual makes JZ mandatory for dates of service from July 1, 2023, and both modifiers are tied to the drug refund calculation.
02Can I use JZ for a partial vial?
Yes, when the leftover is less than a billing unit. CMS does not use fractional units, so a 7 mg dose of a 10 mg unit is billed as one unit with JZ and no JW line. When the dose is at least one billing unit and part of the container is discarded, the discarded units go on a JW line.
03Do skin substitutes need JZ in 2026?
Not for an entire non-BLA skin substitute. From January 1, 2026, these products are paid as incident-to supplies, not drugs, so JZ is not appropriate when the whole product is used. If part is discarded, only the administered units are billable and JW cannot be used.
04Do RHC and FQHC claims need JZ?
No. The JW and JZ policy does not apply to drugs administered in a rural health clinic or FQHC, because drugs there are generally not separately payable. Their cost sits in the clinic's all-inclusive rate or the FQHC prospective payment rate for the visit.
05What happens if I leave JZ off a drug line?
Claims for drugs furnished on or after July 1, 2023 without JW or JZ can be audited. From October 1, 2023 they may be returned as unprocessable until you resubmit correctly. Treat the return as a billing fix, because unprocessable claims carry no appeal rights.
Drug Claims Coming Back?
We check the modifier on every single-dose drug line before the claim is billed.