Overview
Modifier JZ carries the CMS descriptor "zero drug amount discarded/not administered to any patient". CMS added it to the HCPCS file effective January 1, 2023 as the counterpart of JW, which has reported discarded drug for years. The two modifiers work as a pair: every claim line for a separately payable Part B drug that comes from a single-dose container or single-use package should now say either that some of the drug was thrown away (a separate JW line for the discarded units) or that none was (JZ on the administered line). Chapter 17, section 40 of the Medicare Claims Processing Manual makes JZ mandatory for A/B MACs and DME MACs from July 1, 2023. CMS uses the JW and JZ data when it calculates the refunds manufacturers owe for discarded amounts of single-dose container drugs under the discarded-drug provision of the 2021 Infrastructure Investment and Jobs Act, so a missing modifier is a data gap as well as a billing error.
The policy reaches further than many practices expect. It applies to every drug separately payable under Part B that FDA labeling describes as single-dose or single-use, including multiple-source drugs and contrast agents that are not themselves subject to a refund. It does not apply to drugs from multiple-dose containers, to drugs that are not separately payable (packaged OPPS or ASC drugs, or drugs given in a federally qualified health center or rural health clinic), or to the Part B vaccines described in section 1861(s)(10) of the Social Security Act, which mass immunizers often roster bill.
On the claim, the administered line carries the drug's HCPCS code, the JZ modifier and the number of billing units given. The manual adds a rule that trips up dose rounding: when one billing unit is equal to or larger than the dose plus the remainder, billing the remainder with JW is not permitted, because it would overpay, so the single unit is billed with JZ even though part of the vial was discarded. Neither modifier requires the lines to add up to whole vials. Suppliers that do not administer the drug follow the same logic since January 1, 2025: JW when amounts are discarded during preparation, JZ when nothing is.
Operationally, JZ is best captured where the drug is prepared rather than reconstructed at coding. The administration record should show the dose given and the container size, which is the evidence that nothing was left over. Charge capture rules that pair the HCPCS code with either JZ or a JW line, and claim edits that stop a single-dose drug line carrying neither, keep the requirement from depending on memory.
Worked example
An infusion center gives a Medicare patient 300 mg of a drug supplied only in 300 mg single-dose vials, with a HCPCS billing unit of 10 mg. Nothing remains in the vial, so the claim carries one line: the drug's HCPCS code, modifier JZ and 30 units. The next patient receives 280 mg from the same size of vial. That claim carries two lines: the HCPCS code with 28 units and no modifier, and the same code with modifier JW and 2 units for the 20 mg discarded, which the nurse records in the chart.
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Frequently asked questions — Modifier JZ (Zero Drug Amount Discarded)
Is the JZ modifier required on every drug claim?
No. Medicare requires JZ only for drugs separately payable under Part B that come from a single-dose container or single-use package and had no discarded amount. Drugs from multiple-dose vials, packaged OPPS or ASC drugs, drugs given in an FQHC or RHC, and the Part B vaccines in section 1861(s)(10) do not take JW or JZ.
Can JW and JZ appear on the same claim line?
No. JZ goes on the administered line when nothing was discarded. When some was, the administered line carries no wastage modifier and a second line with JW reports the discarded units. A drug therefore has either a JZ line or an unmodified line plus a JW line, never both modifiers together.
What if the dose is smaller than one billing unit?
Bill the single unit with JZ. Chapter 17, section 40 does not allow a JW line when one billing unit already covers the dose and the remainder, because paying the remainder again would overpay; the manual tells contractors to expect JZ in that situation.
Do Medicare Advantage and commercial plans require JZ?
The requirement in the Claims Processing Manual binds Medicare fee-for-service contractors. Medicare Advantage and commercial plans set their own drug billing policies; many follow the CMS approach, so check the plan's policy before assuming the modifier is optional.
Disclaimer
This glossary entry is operational reference for revenue-cycle and medical-billing professionals. It is not legal, clinical, or contractual advice. Industry benchmarks cite named public sources where available; always verify against the current guidance from the authority body before relying on a number in a contract, policy, or compliance filing.