QZ is a HCPCS anesthesia payment modifier meaning "CRNA service: without medical direction by a physician." It tells the payer that a certified registered nurse anesthetist personally performed the anesthesia service without an anesthesiologist medically directing the case. Under Medicare, a QZ-modified anesthesia claim is paid at 100% of the anesthesia fee schedule allowance to the CRNA — in contrast to the medical direction arrangement, where payment is split between the physician (QK or QY) and the CRNA (QX) at 50% each.
Append QZ to the anesthesia CPT code when the CRNA performed the case independently — no anesthesiologist met the medical direction requirements for that case. This includes true independent practice (including in states that have opted out of the federal physician supervision requirement) and cases where an anesthesiologist was generally available but did not perform and document the seven medical direction steps. Every anesthesia claim line needs exactly one provider-role payment modifier, so QZ takes the place of QX/QK/QY/AA — it is never combined with them on the same line.
Do not report QZ when an anesthesiologist actually medically directed the case — that arrangement is reported with QK or QY on the physician claim and QX on the CRNA claim, each paid at 50%. Do not use QZ as a fallback for sloppy medical-direction documentation while the group still bills the physician side; billing QZ for the CRNA and any direction-based code for a physician on the same case is contradictory and a classic audit flag. Do not confuse QZ with QX ("CRNA service with medical direction") — swapping the two changes who gets paid and how much. QZ also does not apply to anesthesiologist assistants, who bill under the QX framework because they must work under direction.
The anesthesia record should make the staffing model unambiguous: the CRNA as the anesthesia provider of record, with no physician documented as performing the medical direction elements (pre-anesthetic evaluation, prescribing the plan, presence at induction, monitoring, availability, and the rest of the seven steps). State supervision requirements and facility bylaws still apply clinically, but the QZ modifier is a payment statement about medical direction, not about whether any physician was in the building — the record just needs to be internally consistent with the modifier billed.
The CRNA receives 100% of the Medicare anesthesia fee schedule allowance for the case, calculated from base units plus time units and the conversion factor — the same total that would be paid for a personally performed physician case under AA.
No. QZ reflects the absence of medical direction, which is a billing concept. A CRNA in a non-opt-out state can still bill QZ when no anesthesiologist performed the medical direction steps — clinical supervision requirements are a separate matter governed by state law and facility policy.
Not for directing that anesthesia case. A same-case physician claim with a direction modifier contradicts the QZ and invites recoupment of one side or both. A physician could still bill genuinely separate, distinct services if they occurred and are documented.
Payment is wrong in one direction or the other: QX pays the CRNA 50% expecting a matching physician claim, while QZ pays 100% expecting none. Systematic misuse in either direction creates overpayments that payers can recover, so modifier assignment should be reconciled against the staffing documented in each anesthesia record.
Coding questions like this one are where revenue leaks start. See how Medtransic supports anesthesiology practices with certified billing and denial management: Anesthesiology Billing Services.