CPT Modifiers Cheat Sheet: 90 CPT and HCPCS Modifiers in Plain English

What it tells the payerThe provider did a clearly separate, well-documented visit on top of the procedure, not just the usual check-in that comes with it.

Related: CPT 93000 ECG modifiers.

Use it whenA patient comes in for a problem and also needs a minor procedure, and the note shows a real visit (history, exam, decision-making) beyond the pre-procedure routine.

Related: hysterectomy CPT code modifiers.

Watch out forIt goes on the E/M code, not the procedure. It is not for the routine work built into the procedure. The OIG has found it misused (see the compliance notes).

What it tells the payerThe visit is where the provider decided the patient needs a major surgery, and it falls on the day of that surgery or the day before.

Use it whenYou are billing the E/M visit at which the decision for a major (90-day global) procedure was made.

Watch out forMajor surgery only. It is not for visits that did not decide the surgery. For a minor procedure, ask whether modifier 25 fits instead.

What it tells the payerA visit during the global period of an earlier procedure that has nothing to do with that procedure.

Use it whenThe patient is still inside the global period and comes in about a different, unrelated problem.

Watch out forVisits about the surgery itself (pain, wound checks, suture removal) belong to the global package and are not billed separately. The note must make the difference clear.

What it tells the payerA staged or planned second procedure, or a more extensive one, related to the first, done while the global period is running.

Use it whenThe second stage was planned from the start, or the follow-up goes further than the original procedure.

Watch out forIf the return was unplanned because of a complication, look at 78. If the new procedure is unrelated to the first, look at 79.

What it tells the payerSomething went wrong after the procedure and the patient had to go back to the operating room for a related problem.

Use it whenA related complication needs treatment in the operating room during the global period.

Watch out forIt must be both unplanned and related. Planned follow-ups are 58. Unrelated procedures are 79.

What it tells the payerA different procedure, unrelated to the first, done while the first one’s global period is still running.

Use it whenThe new procedure treats a different problem and the note shows it.

Watch out forCMS’s booklet says a new global period begins with the unrelated procedure.

What it tells the payerThe surgeon did the operation but handed the after-care to someone else.

Use it whenThere is a formal transfer of care and the surgeon provides no post-op care.

Watch out forIt pairs with 55 from the provider who takes over. CMS’s booklet describes a formal, written transfer of care.

What it tells the payerYou manage the patient’s recovery after someone else did the surgery.

Use it whenThe surgeon formally handed over the post-operative care and you accepted it.

Watch out forDo not bill it without the transfer arrangement. CMS’s booklet calls for a written agreement. Cataract co-management is a common case in ophthalmology medical billing services.

What it tells the payerYou did the pre-operative care, but a different provider did the surgery.

Use it whenPre-operative services were handed over under a formal transfer of care.

Watch out forThe surgeon’s side of the same arrangement is 54. CMS’s booklet calls for a formal transfer agreement.

What it tells the payerThe same provider did more than one procedure at the same session.

Use it whenTwo or more different procedures in one session, none of them add-on codes.

Watch out forPayers usually pay the lower-valued procedures at a reduced rate. Add-on codes are generally exempt. Some payers add the reduction themselves and do not want 51 on the claim, so check the payer.

What it tells the payerTells the payer that two procedures an edit would normally bundle were really separate: a different site, session or practitioner.

Use it whenAn NCCI edit bundles two codes, the edit allows a modifier, and the note shows the services were separate. See our urology billing services for how 59, XU and 52 apply to cystoscopy and prostate biopsy claims.

Watch out forCMS says to use XE, XP, XS or XU when one fits and 59 only if nothing more specific applies. It is not for E/M visits (use 25) and not a fix because the diagnoses differ.

What it tells the payerThe service was distinct because it happened during a separate encounter, such as a different visit later the same day.

Use it whenThe two services were truly separate encounters and the note shows when each happened.

Watch out forIt does not cover two services in one session. Document the separate encounter.

What it tells the payerThe service was distinct because it was done on a separate organ or structure.

Use it whenTwo procedures that an edit bundles were done on different organs or different structures.

Watch out forWork on the same structure, or overlapping work, does not qualify. The note should name each structure.

What it tells the payerThe service was distinct because a different practitioner performed it.

Use it whenA second practitioner did the other service and the note shows who did what.

Watch out forCheck the payer’s rule on what counts as a different practitioner before using it.

What it tells the payerThe service was distinct because it does not overlap the usual components of the main service.

Use it whenNone of XE, XS or XP describes why the service is separate, but it truly shares nothing with the main procedure’s usual work.

Watch out forTreat it as the last X modifier to reach for. CMS wants documentation that supports the choice.

What it tells the payerThe same provider had to do the same procedure again after the original.

Use it whenThe repeat was needed for a clinical reason, such as a change in the patient’s condition, and the note says why.

Watch out forIt does not bypass an NCCI edit. It is not for redoing a test because of a technical problem.

What it tells the payerA different provider repeated a procedure that someone else did first.

Use it whenA second provider had to redo the procedure and the note says why.

Watch out forIt does not bypass an NCCI edit. Compare 76 for a repeat by the same provider.

What it tells the payerA lab test was repeated on the same day because a further result was needed, such as tracking a trend.

Use it whenThe clinical picture called for the same test again that day and the new result is the point.

Watch out forNot for rerunning a test to confirm an odd result or because of an equipment or specimen problem. NCCI mentions 91 for a repeated component of a lab panel.

What it tells the payerThe procedure was much harder or took much longer than the code normally assumes.

Use it whenThere was unusual difficulty (extra time, scar tissue, unusual anatomy) and the note documents it with specifics.

Watch out forIt does not bypass an NCCI edit. Payers usually want a short explanation, and many ask for the note.

What it tells the payerPart of the procedure was not done, by the provider’s choice, so the full code overstates what happened.

Use it whenThe planned procedure was cut back, but not because of a safety problem.

Watch out forExpect lower payment and be ready to explain. If it was stopped for patient safety, see 53.

What it tells the payerThe procedure was started and then stopped because continuing would have put the patient at risk.

Use it whenA complication or an unstable patient made the provider stop.

Watch out forNot for a procedure that was cancelled before it began. For a deliberate cut-back, see 52.

What it tells the payerTwo surgeons, usually of different specialties, each do a distinct part of one procedure, and each bills the same code with 62.

Use it whenBoth surgeons are needed for the one operation and each documents their part.

Watch out forCMS’s booklet puts each surgeon’s payment at 62.5 percent of the fee. Check the payer and the fee schedule for whether the code allows co-surgeons.

What it tells the payerA physician assisted the surgeon during the procedure.

Use it whenAn assisting physician bills the surgical code with 80, for a procedure that allows an assistant.

Watch out forMedicare pays a physician who assists at surgery 16 percent of the amount otherwise payable for the surgery, and only for procedures that allow an assistant.

What it tells the payerA physician assisted for only a short or minimal part of the procedure.

Use it whenThe assisting physician’s involvement was brief and the payer recognizes this modifier.

Watch out forNot every payer accepts it, so check the payer before you rely on it.

What it tells the payerIn a teaching setting, a physician assisted because no qualified resident surgeon was available.

Use it whenIt is added to the assistant-at-surgery reporting when the note shows no qualified resident was available.

Watch out forThe unavailability of a resident is the whole point of the modifier, so the record should say so.

What it tells the payerA physician assistant, nurse practitioner or clinical nurse specialist assisted the surgeon.

Use it whenA non-physician practitioner assisted on a procedure that allows an assistant.

Watch out forCheck the payer for whether the procedure allows an assistant at all and how much it pays.

What it tells the payerThe same procedure was done on both sides of the body in one session.

Use it whenThe code describes one side and the provider treated both.

Watch out forNot when the code descriptor already says bilateral. Do not add LT or RT on top of 50. Some payers want two lines with LT and RT instead of 50, so check.

What it tells the payerThe procedure was on the left side of the body.

Use it whenThe procedure is one-sided and the code does not say which side.

Watch out forDo not combine it with 50. NCCI lists LT and RT among the modifiers that may bypass an edit when the facts support it.

What it tells the payerThe procedure was on the right side of the body.

Use it whenThe procedure is one-sided and the code does not say which side.

Watch out forDo not combine it with 50. NCCI lists LT and RT among the modifiers that may bypass an edit when the facts support it.

What it tells the payerE1 upper left eyelid, E2 lower left eyelid, E3 upper right eyelid, E4 lower right eyelid.

Use it whenAn eyelid procedure where the payer wants to know which eyelid was treated.

Watch out forChoose the modifier that matches the operative note.

What it tells the payerFA left thumb, F1 to F4 left fingers 2 to 5, F5 right thumb, F6 to F9 right fingers 2 to 5.

Use it whenA finger or thumb procedure where each digit is reported on its own line.

Watch out forDigits are numbered from the thumb: FA and F5 are the thumbs. The note should say which finger was treated.

What it tells the payerTA left great toe, T1 to T4 left toes 2 to 5, T5 right great toe, T6 to T9 right toes 2 to 5.

Use it whenA toe procedure where each toe is reported on its own line.

Watch out forToes are numbered from the great toe: TA and T5 are the great toes. The note should say which toe was treated.

What it tells the payerLC left circumflex, LD left anterior descending, LM left main, RC right coronary, RI ramus intermedius.

Use it whenA heart procedure where the payer wants to know which coronary artery was treated.

Watch out forUse the artery named in the procedure note. NCCI lists all five among the modifiers that may bypass an edit.

What it tells the payerYou are billing only the provider’s reading or interpretation of a test, not the equipment and staff cost.

Use it whenA code with separate professional and technical parts, and your practice supplies only the interpretation. ECG, echo and stress-test claims in cardiology often split this way; see our cardiology billing services.

Watch out forWhen one practice supplies both the equipment and the reading, it normally bills the code with neither 26 nor TC. CMS has a recovery audit topic for incorrect 26 and TC coding.

What it tells the payerYou are billing only the equipment, supplies and staff part of a test, not the reading.

Use it whenA code with separate professional and technical parts, and your practice supplies only the technical side.

Watch out forDo not add it when you bill the whole service. CMS has a recovery audit topic for incorrect TC and 26 coding.

What it tells the payerThe lab test is a CLIA-waived test performed at a site that holds the CLIA waiver.

Use it whenYou run an in-office waived test and bill it to Medicare.

Watch out forCMS says to include QW so Medicare recognizes the code as a waived test, and it edits lab claims by the site’s CLIA status.

What it tells the payerA required Advance Beneficiary Notice was issued and is on file.

Use it whenMedicare may deny the service as not reasonable and necessary, and you gave the patient the required notice first.

Watch out forThe notice does not need to travel with the claim but must be available if asked. These four are Medicare notice modifiers; other payers have their own rules.

What it tells the payerA voluntary notice was issued for a service Medicare never covers.

Use it whenThe service is excluded by statute or is not a Medicare benefit, and you chose to give the patient a notice anyway.

Watch out forIt is the voluntary-notice modifier. Compare GY when no notice was given.

What it tells the payerMedicare excludes the item or service by statute, or it is not a Medicare benefit, and no notice was issued.

Use it whenYou are billing Medicare for an item or service that it excludes by statute or that is not a Medicare benefit.

Watch out forCompare GX when a voluntary notice was given.

What it tells the payerYou expect Medicare to deny the service as not medically necessary, and no notice was issued.

Use it whenA required notice was not given and you still expect a medical necessity denial.

Watch out forIf a required notice was given, the modifier is GA instead.

What it tells the payerThe chiropractic manipulation was active or corrective treatment, not maintenance.

Use it whenMedicare chiropractic manipulation codes 98940, 98941 and 98942 for active treatment. See our chiropractic billing services for how AT, GA and GZ fit together.

Watch out forCMS says Medicare requires AT to pay those codes. It does not prove medical necessity, and it must not be used for maintenance therapy, which Medicare does not pay.

What it tells the payerPart of a single-dose container or single-use package was thrown away and you are billing the wasted amount.

Use it whenA separately payable Part B drug came in a single-dose container or single-use package and some of it was discarded.

Watch out forThe administered amount is billed without the modifier. If nothing was discarded, see JZ.

What it tells the payerYou are telling Medicare that none of the drug was discarded.

Use it whenCMS requires it on claims for separately payable Part B drugs from single-dose containers or single-use packages when no amount was discarded.

Watch out forIf some was discarded, the discarded amount carries JW instead.

What it tells the payerThe service was delivered under an outpatient speech-language pathology plan of care.

Use it whenMedicare outpatient speech-language pathology claims.

Watch out forCMS requires the discipline modifier on applicable therapy codes. Match it to the plan of care.

What it tells the payerThe service was delivered under an outpatient occupational therapy plan of care.

Use it whenMedicare outpatient occupational therapy claims.

Watch out forCMS requires the discipline modifier on applicable therapy codes. Match it to the plan of care.

What it tells the payerThe service was delivered under an outpatient physical therapy plan of care.

Use it whenMedicare outpatient physical therapy claims.

Watch out forCMS requires the discipline modifier on applicable therapy codes. Match it to the plan of care. See how our physical therapy billing services team applies it to Medicare therapy lines.

What it tells the payerAn outpatient physical therapy service was furnished in whole or in part by a physical therapist assistant.

Use it whenA PTA performed all or part of the service.

Watch out forSince January 1, 2022, CMS pays these services at 85 percent of the otherwise applicable amount. See how our physical therapy billing services team flags assistant-furnished visits at charge entry.

What it tells the payerAn outpatient occupational therapy service was furnished in whole or in part by an occupational therapy assistant.

Use it whenAn OTA performed all or part of the service.

Watch out forSince January 1, 2022, CMS pays these services at 85 percent of the otherwise applicable amount.

What it tells the payerFor Medicare therapy, it confirms the services are medically necessary after the patient is past the KX threshold of incurred expenses.

Use it whenThe patient has passed the threshold and the record supports continued therapy.

Watch out forIt does not replace the documentation. The threshold changes by year, so use CMS’s current figure. See how our physical therapy billing services team tracks the threshold by patient.

What it tells the payerThe service was delivered by real-time, two-way audio and video.

Use it whenYour payer’s current telehealth policy asks for it.

Watch out forPayers differ on whether they want 95, GT or none, and on place of service 02 or 10. CMS’s December 2025 booklet mentions 95 for outpatient therapy by hospital-employed therapists on institutional claims.

What it tells the payerThe service was delivered through interactive audio and video telecommunications.

Use it whenYour payer still asks for it.

Watch out forIn CMS’s December 2025 booklet, GT appears for distant-site practitioners under the CAH optional payment Method II on institutional claims.

What it tells the payerThe service was delivered by telephone or other audio-only means.

Use it whenYour payer asks for a modifier on audio-only services.

Watch out forPolicies on audio-only visits change often and differ by payer. Check the payer’s current rules; we did not find a CMS source to cite for it.

What it tells the payerThe service was furnished using audio-only communication technology.

Use it whenYour payer asks for the Level II audio-only modifier.

Watch out forCheck the payer for whether it wants 93, FQ or neither; we did not find a CMS source to cite for it.

What it tells the payerThe anesthesiologist personally performed the anesthesia service.

Use it whenNo CRNA or resident is involved in the anesthesia you are billing.

Watch out forThe anesthesia modifiers describe who did what. Payment rules differ by payer.

What it tells the payerA physician supervised more than four concurrent anesthesia procedures.

Use it whenThe supervising physician had more than four cases running at once.

Watch out forPayers treat it differently from medical direction (QK, QY). Check the payer’s policy.

What it tells the payerA physician medically directed two, three or four concurrent anesthesia procedures involving qualified individuals.

Use it whenOne physician directed up to four overlapping cases.

Watch out forPair it with the right modifier for the person doing the case (QX for a CRNA). Payment rules differ by payer.

What it tells the payerA nurse anesthetist performed the service with medical direction by a physician.

Use it whenA CRNA did the case and an anesthesiologist directed it.

Watch out forThe physician side of the same case is QK or QY.

What it tells the payerAn anesthesiologist medically directed one qualified nurse anesthetist.

Use it whenThe anesthesiologist directed a single CRNA case.

Watch out forThe CRNA side of the same case is QX.

What it tells the payerA nurse anesthetist performed the service without medical direction by a physician.

Use it whenThe CRNA worked independently.

Watch out forIf a physician directed the case, the CRNA’s modifier is QX.

What it tells the payerP1 normal healthy patient, P2 mild systemic disease, P3 severe systemic disease, P4 severe disease that is a constant threat to life, P5 moribund patient not expected to survive without the operation, P6 declared brain-dead patient whose organs are being removed for donation.

Use it whenAnesthesia claims where the payer pays for the patient’s physical status.

Watch out forASA says Medicare does not pay extra for physical status, but many private payers do.