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CPT Modifiers List 2026: The Ones Billers Actually Use

Every modifier below changes either what gets paid or whether the claim survives an edit. Grouped by what they do, with the classic mistake for each — because most modifier denials aren't coding errors, they're category errors.

Modifier	When to use it	Watch out
22 Increased procedural services	Work substantially greater than typically required — document why (severity, difficulty, time).	Requires documentation with the claim; expect manual review. Not an NCCI bypass modifier.
24 Unrelated E/M during a global period	E/M by the same physician during a post-op global period, unrelated to the surgery.	The note must stand alone as unrelated — diagnosis linkage matters.
25 Significant, separately identifiable E/M	E/M on the same day as a minor procedure (0/10-day global), beyond the decision to perform it.	The most audited modifier in billing. Same diagnosis is allowed; separate documentation is what wins. See the full guide.
26 Professional component	Physician interpretation only (e.g., reading an X-ray owned by the facility).	Pair-check: the facility bills TC. Billing global (no modifier) when you only did the read is an overpayment.
TC Technical component	Equipment/staff portion only — the entity that owns the machine.	Never billable by the interpreting-only physician.
50 Bilateral procedure	Same procedure, both sides, same session.	Payer-specific: some want 50 on one line at 150%, others want RT/LT on two lines. Check the fee schedule.
51 Multiple procedures	Additional procedures, same session (payment usually reduced 50%).	Most systems apply multiple-procedure reduction automatically — appending 51 unnecessarily can double-reduce.
52 Reduced services	Service partially reduced/eliminated at physician discretion.	Expect a proportional payment cut; document what was omitted and why.
53 Discontinued procedure	Procedure stopped after starting due to patient risk.	Different from 52: 53 = stopped for wellbeing, 52 = planned reduction.
57 Decision for surgery	E/M that resulted in the decision to perform a MAJOR surgery (90-day global) that day or the next.	25 is for minor procedures; 57 is for major. Swapping them is an instant denial.
58 Staged or related procedure	Planned/staged or more extensive procedure during the global period.	Starts a new global period. Not for return-to-OR complications — that's 78.
59 Distinct procedural service	Bypass an NCCI bundling edit when procedures were truly separate (site, session, lesion, injury).	The OIG found 40% of modifier-59 pairs failed requirements. Use an X modifier when one fits. See the full guide.
XE Separate encounter	Distinct because it occurred in a separate encounter on the same day.	More specific than 59 — CMS prefers it when it applies.
XS Separate structure	Distinct because performed on a separate organ/structure.	Not for contiguous structures in the same organ/region. If RT/LT applies, use those instead.
XP Separate practitioner	Distinct because performed by a different practitioner.	Same group/specialty may still be treated as the same practitioner by payers.
XU Unusual non-overlapping service	Distinct because it doesn't overlap the usual components of the main service.	The vaguest X — expect scrutiny similar to 59 itself.
62 Two surgeons	Co-surgeons, each performing a distinct part of one procedure.	Both must append 62 and document their distinct portions; payment typically 62.5% each.
76 Repeat procedure — same provider	Same procedure repeated same day by the same provider.	Use instead of 59 for repeats — 59 for a repeat is a classic misuse.
77 Repeat procedure — different provider	Same procedure repeated same day by a different provider.	Documentation should show why the repeat was necessary.
78 Unplanned return to OR	Related procedure requiring return to the OR during the global period.	Payment reduced (intra-op portion only); global period does not reset.
79 Unrelated procedure during global	Unrelated procedure by the same physician during a global period.	New global period starts; diagnosis should clearly differ from the original surgery.
80 Assistant surgeon	Physician assisting at surgery.	Check the MPFS assistant-surgery indicator first — many codes never pay an assistant.
AS PA/NP assistant at surgery	Non-physician practitioner assisting at surgery.	Paid at a reduced assistant rate; same indicator check as 80.
91 Repeat clinical lab test	Medically necessary repeat of the same lab test, same day (e.g., serial potassium).	Not for rerun-due-to-error or confirmatory testing — that's not billable twice.
95 Synchronous telehealth (audio-video)	Real-time interactive audio-video service.	Pair with the right POS (02 vs 10) — the POS drives the payment rate for most payers.
93 Audio-only telehealth	Real-time interactive audio-only service.	Only for services payers allow audio-only; coverage is narrower than 95.
FQ Audio-only behavioral health	Medicare behavioral health via audio-only.	Medicare-specific; commercial payers may want 93 instead.
GT Telehealth (legacy)	Historic Medicare telehealth modifier, still required by some commercial/Medicaid payers.	Medicare replaced GT with 95 + POS for most claims years ago — payer-specific, check before defaulting.
GA ABN on file (expected denial)	Medicare: ABN signed for a service expected to be denied as not reasonable/necessary.	Shifts liability to the patient — without GA, you likely can't bill them after denial.
GX Voluntary ABN for excluded service	ABN issued voluntarily for a statutorily excluded service.	Often paired with GY.
GY Statutorily excluded	Service is never a Medicare benefit — generates a denial for secondary billing.	Used deliberately to get the denial that unlocks the secondary payer.
GZ Expected denial, no ABN	Expected not-reasonable-necessary denial and no ABN was obtained.	Auto-denied and provider-liable — GZ is an honesty modifier, not a payment one.
KX Requirements met	Attests documentation requirements in the applicable policy are met (e.g., therapy threshold).	An attestation with audit teeth — only append when the record genuinely supports it.
LT Left side	Anatomic: procedure on the left side.	Prefer RT/LT over 59/XS when laterality is the actual distinction.
RT Right side	Anatomic: procedure on the right side.	Same rule — anatomic modifiers beat 59 when they apply.
QW CLIA-waived test	Lab test performed under a CLIA waiver.	Missing QW on a waived test with a waiver-level CLIA number = automatic rejection.

Reference summaries based on CPT® definitions and the 2026 Medicare NCCI Policy Manual. Payer-specific payment rules vary — verify against the payer's fee schedule and policy. CPT is a registered trademark of the AMA.

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Free download: 2026 Modifier Cheat Sheet (PDF)

This entire table as a printable two-page desk reference — every modifier, when to use it, and the mistake that gets it denied.

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The two modifiers that cause the most damage

If your denial reports show CO-97 (bundled) or CO-11 (coding) clusters, the root cause is almost always one of two modifiers. Modifier 25 — the E/M-with-procedure modifier — is the single most audited code in billing, and several major payers now apply documentation review or automatic payment reductions to it. Modifier 59 — the bundling-bypass modifier — is the one the OIG found misused in 40% of sampled claims, and the reason CMS created the X-modifier family. We've written a full working guide for each.

Modifier problems show up as revenue problems

Underuse leaves earned E/M revenue unbilled; overuse invites audits and recoupment. Our coders find both in nearly every audit we run — see where your practice sits.

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