Need help choosing the right code?
Ask CasePilot about procedures, modifiers, bundling, and coding guidance.
Try CasePilotCPT 00811 is the default anesthesia code for any lower intestinal endoscopic procedure not already captured by 00812 or 00813. The scope must be introduced distal to the duodenum; procedures in which the scope enters proximal to the duodenum (esophagus, stomach, duodenum) are coded separately.
Clinical indications that map to 00811:
Scope boundary: The "not otherwise specified" designation means 00811 is the residual code for lower GI endoscopic anesthesia. If the procedure is specifically a screening colonoscopy, the intent governs: 00812 is required. If the single anesthesia encounter covers both an upper GI procedure (e.g., EGD) and a lower GI procedure, 00813 captures the combined session.
Provider requirement: Only a separate anesthesia provider may bill 00811. The gastroenterologist or colorectal surgeon performing the endoscopy cannot bill anesthesia codes for their own procedure. If the performing physician administers moderate sedation themselves (without a separate anesthesia provider), the applicable codes are 99151/99153 (physician performing the procedure) or 99155/99157 (second physician in facility setting), not 00811.
Anesthesia time: Time begins when the anesthesia provider starts preparing the patient for induction in the procedure area and ends when the patient is safely transferred to a post-anesthesia care provider. Pre- and post-anesthesia evaluation time is included in the base service and is not separately billable. Medicare reports time in 15-minute units (1 unit per 15 minutes). Total payment = (base units + time units + modifying units) x the locality-specific anesthesia conversion factor.
| Code | Description | When to Use Instead |
|---|---|---|
| 00811 | Anesthesia, lower intestinal endoscopic; NOS | Default for all diagnostic, therapeutic, and surveillance lower GI endoscopy |
| 00812 | Anesthesia, lower intestinal endoscopic; screening colonoscopy | Documented intent is routine colorectal cancer screening; drives Medicare preventive benefit (no patient cost-sharing) |
| 00813 | Anesthesia, combined upper and lower GI endoscopic procedures | Same anesthesia encounter covers both an EGD-range procedure (proximal to duodenum) and a colonoscopy-range procedure (distal to duodenum) |
| 00810 | Anesthesia, lower intestinal endoscopic (deleted) | Never. Deleted effective 2017-12-31. Claims will deny; use 00811, 00812, or 00813 |
The single most important differentiator is the documented procedure intent. A colonoscopy ordered to evaluate symptoms, a positive stool test, a prior polyp, or a genetic syndrome is not a screening colonoscopy regardless of what the procedure itself looks like. The gastroenterologist's procedure report and the ordering indication in the medical record establish whether 00811 or 00812 applies. When a screening colonoscopy is converted intraoperatively to a diagnostic or therapeutic procedure, modifier PT appended to the surgical code addresses the cost-sharing conversion; the anesthesia code selection should reflect the final documented intent.
Personnel modifiers (required on all Medicare claims):
| Modifier | Scenario | Medicare Payment |
|---|---|---|
| AA | Anesthesiologist personally performs the entire service | 100% of allowed amount |
| QK | Anesthesiologist medically directs 2 to 4 concurrent CRNA or AA procedures | 50% per procedure |
| QX | CRNA service under anesthesiologist medical direction | 50% per procedure |
| QY | Anesthesiologist medically directs exactly one CRNA | 50% per procedure |
| QZ | CRNA service without any physician medical direction | 100% of allowed amount |
| AD | Physician medically supervises more than 4 concurrent anesthesia procedures | Capped at 3 base units |
Physical status modifiers: Append one physical status modifier (P1 through P5) to every anesthesia claim. P1 and P2 add zero modifying units under Medicare; P3 adds one unit, P4 adds two, P5 adds three. Physical status must be assigned before the procedure during the pre-anesthesia evaluation and documented in the medical record.
QS (Monitored Anesthesia Care): QS is informational and identifies the service as MAC rather than general or regional anesthesia. Many payers require it when MAC is billed; it does not affect payment amount under Medicare but supports medical necessity documentation.
PT modifier interaction: PT is appended to the surgical code (e.g., 45378-PT) when a screening colonoscopy converts to a diagnostic or therapeutic procedure, signaling the cost-sharing transition. The anesthesia code does not carry PT; the anesthesia provider should code the procedure as documented at completion.
Add-on code 0887T: Report separately in addition to 00811 when end-tidal control of inhaled anesthetic agents and oxygen is used. This 2024 code is carrier-priced under MPFS and is listed in the CPT codebook as reportable in conjunction with anesthesia procedure codes 00100 through 01999.
Qualifying circumstances:
Bundling: Anesthesia codes are not bundled with the surgical procedure codes in NCCI PTP edits when separate providers bill them. The gastroenterologist's 45378, 45380, 45385, 45388, 45390, or 45330 and the anesthesiologist's 00811 are billed independently. MUE for 00811 is not applicable per current data, consistent with anesthesia codes as a class.
Required anesthesia record elements:
MAC-specific documentation: Payers and auditors scrutinize MAC claims for colonoscopy because moderate sedation by the endoscopist is considered the standard for routine procedures in many populations. Documentation must affirmatively establish why a separate anesthesia provider and MAC level monitoring were medically necessary. Accepted justifications include: inability to tolerate standard sedation, significant cardiopulmonary comorbidity, obesity, anticipated complex or prolonged procedure, prior failed sedation, chronic opioid/benzodiazepine use, or patient/procedure factors documented by the ordering gastroenterologist in the procedure request or pre-op note.
Procedure intent documentation: Because the anesthesia code selection (00811 vs. 00812) follows the procedure intent, the gastroenterologist's procedure indication and final report are part of the audit trail for the anesthesia claim. Coders should reconcile the anesthesia record with the endoscopist's operative report before finalizing the code.
Audit red flags specific to 00811:
Medicare:
CMS pays anesthesia claims under the Medicare Physician Fee Schedule using the base-plus-time formula with a locality-specific anesthesia conversion factor updated annually. Because the anesthesia conversion factor varies by geographic area, reimbursement for the same 00811 claim differs by MAC jurisdiction and even by county in some states. Verify the current conversion factor through the CMS MPFS Lookup Tool.
In the hospital outpatient department, the APC status indicator for 00811 is "Items and Services Packaged into APC Rates." This means the facility does not receive a separate APC payment for anesthesia; it is bundled into the facility's APC rate for the surgical procedure. However, the professional anesthesia claim (00811 billed by the anesthesiologist or CRNA group) is still separately paid under the professional MPFS and is not affected by facility packaging.
MAC medical necessity for colonoscopy is addressed by MAC-specific Local Coverage Determinations. Because LCDs vary by jurisdiction, providers must confirm applicable LCD requirements with their regional Medicare Administrative Contractor. The absence of a current LCD does not eliminate the documentation burden; medical necessity for MAC remains a coverage condition regardless.
Commercial payers:
Physical status P2 may carry an additional base unit value under some commercial contracts (versus zero additional units under Medicare). Anesthesia groups should verify physical status modifier payment rules in each commercial contract. Some commercial payers require prior authorization for elective MAC services for colonoscopy, particularly when the clinical justification is primarily patient preference rather than a documented medical condition. Modifier QS designation for MAC may be contractually required or informational depending on the payer.
Modifier PT and cost-sharing conversion: When a screening colonoscopy converts to a therapeutic procedure, the anesthesia team should confirm with the billing department whether the payer applies the PT modifier logic to the anesthesia claim, the surgical claim, or both. Medicare rules apply PT only to the surgical code, not the anesthesia code, but the downstream cost-sharing impact on the patient applies to the entire encounter.
Denial: Missing personnel modifier
Anesthesia claims submitted to Medicare without AA, QK, QX, QY, QZ, QY, or AD are automatically denied. Root cause is usually a billing system configuration error or template missing the modifier field. Prevention: implement a charge capture edit that rejects 00811 claims leaving the billing system without a personnel modifier.
Denial: Incorrect code selection (00811 billed for screening colonoscopy)
Medicare processes 00811 as a diagnostic/therapeutic anesthesia service and applies standard cost-sharing. If the underlying procedure was a preventive screening, the patient faces incorrect cost liability and the payer may recoup on post-payment audit. Prevention: reconcile the anesthesia code against the gastroenterologist's procedure report at claim submission. If the operative report indicates a screening indication or the surgical code carries a preventive service designation, verify whether 00812 applies.
Denial: MAC not medically necessary
Payers, particularly under MAC LCDs, may deny 00811 when the clinical record does not support the need for a separate anesthesia provider. Root cause is MAC provided as a routine convenience or per anesthesia group protocol without patient-specific clinical justification. Prevention: the pre-anesthesia evaluation must document patient-specific risk factors. The procedure request from the gastroenterologist should also document the medical necessity rationale. On appeal, submit the pre-anesthesia evaluation, referring physician's justification, and applicable LCD criteria.
Denial: Physical status upcoding
Auditors flag claims where physical status P3 or P4 is billed but the pre-anesthesia evaluation documents a patient with only mild or no systemic disease. This is a compliance risk beyond a simple denial; it may trigger overpayment recovery and potentially fraud referral if systematic. Prevention: physical status assignment must be made by the anesthesia provider during pre-procedure evaluation and documented explicitly in the record, not inferred or defaulted.
Denial: Deleted code 00810
Claims submitted with 00810 deny outright. This code was deleted effective 2017-12-31. Use 00811, 00812, or 00813 based on procedure intent and scope.
Scenario 1: A 58-year-old patient with rectal bleeding undergoes diagnostic flexible colonoscopy in an ASC. An anesthesiologist personally provides MAC. Pre-anesthesia evaluation documents mild controlled hypertension (ASA P2). Procedure time: 35 minutes (anesthesia time: 45 minutes, 3 units).
Correct coding: 00811-AA-P2 with 3 time units + 5 base units. Gastroenterologist bills 45378.
Why: The indication is rectal bleeding, a diagnostic indication. 00812 does not apply because this is not a screening colonoscopy. P2 is appropriate; P3 would require documentation of a severe systemic disease condition not present here.
Scenario 2: A 74-year-old patient with type 2 diabetes and COPD (ASA P3) undergoes surveillance colonoscopy with snare polypectomy after a prior adenoma. An anesthesiologist personally performs MAC.
Correct coding: 00811-AA-P3 + 99100. Gastroenterologist bills 45385. P3 adds 1 modifying unit; 99100 adds 1 qualifying circumstance unit (patient over 70).
Why: Surveillance colonoscopy carries a clinical indication (prior adenoma); it is not routine screening. Age 74 qualifies for 99100. P3 is supported by diabetes plus COPD documented in the pre-anesthesia evaluation.
Scenario 3: A patient requires EGD for dysphagia evaluation and colonoscopy for GI bleeding in the same encounter. A CRNA administers anesthesia under anesthesiologist medical direction (one of three concurrent cases).
Correct coding: 00813-QX (CRNA claim) and 00813-QK (directing anesthesiologist claim). Do not bill 00811 and a separate upper GI anesthesia code.
Why: The combined upper and lower GI procedure in a single anesthesia session maps to 00813. Billing 00811 and a separate upper GI anesthesia code for the same anesthesia encounter constitutes unbundling.
Scenario 4: A 65-year-old patient undergoes flexible sigmoidoscopy for evaluation of chronic diarrhea. A CRNA provides anesthesia independently with no anesthesiologist present or directing.
Correct coding: 00811-QZ-P1 with time units. Gastroenterologist bills 45330.
Why: Sigmoidoscopy involves a scope introduced distal to the duodenum and falls within 00811's scope. 00812 applies only to screening colonoscopy, not sigmoidoscopy. QZ is correct when the CRNA operates without any physician direction.
© Copyright 2026 American Medical Association. All rights reserved.
| Short Descr | ANES LWR INTST NDSC NOS | Medium Descr | ANESTHESIA LOWER INTST ENDOSCOPIC PX NOS | Long Descr | Anesthesia for lower intestinal endoscopic procedures, endoscope introduced distal to duodenum; not otherwise specified | Status Code | Anesthesia Service | Global Days | XXX - Global Concept Does Not Apply | PC/TC Indicator (26, TC) | 9 - Not Applicable | Multiple Procedures (51) | 9 - Concept does not apply. | Bilateral Surgery (50) | 9 - Concept does not apply. | Physician Supervisions | 09 - Concept does not apply. | Assistant Surgeon (80, 82) | 9 - Concept does not apply. | Co-Surgeons (62) | 9 - Concept does not apply. | Team Surgery (66) | 9 - Concept does not apply. | Diagnostic Imaging Family | 99 - Concept Does Not Apply | APC Status Indicator | Items and Services Packaged into APC Rates | Type of Service (TOS) | 7 - Anesthesia | Berenson-Eggers TOS (BETOS) | none | MUE | Not applicable/unspecified. |
This is a primary code that can be used with these additional add-on codes.
| 0887T | New Code for 2024 Add On Code MPFS Status: Carrier Priced APC N ASC N1 End-tidal control of inhaled anesthetic agents and oxygen to assist anesthesia care delivery (List separately in addition to code for primary procedure) |
| QZ | Crna service: without medical direction by a physician | QS | Monitored anesthesia care service | PT | Colorectal cancer screening test; converted to diagnostic test or other procedure | QK | Medical direction of two, three, or four concurrent anesthesia procedures involving qualified individuals | AA | Anesthesia services performed personally by anesthesiologist | QX | Crna service: with medical direction by a physician | P2 | A patient with mild systemic disease | X4 | Episodic/focused services: for reporting services by clinicians who provide focused care on particular types of treatment limited to a defined period and circumstance; the patient has a problem, acute or chronic, that will be treated with surgery, radiation, or some other type of generally time-limited intervention; reporting clinician service examples include but are not limited to, the orthopedic surgeon performing a knee replacement and seeing the patient through the postoperative period | P3 | A patient with severe systemic disease | QY | Medical direction of one certified registered nurse anesthetist (crna) by an anesthesiologist | G9 | Monitored anesthesia care for patient who has history of severe cardio-pulmonary condition | AD | Medical supervision by a physician: more than four concurrent anesthesia procedures | P1 | A normal healthy patient | P4 | A patient with severe systemic disease that is a constant threat to life | Q6 | Service furnished under a fee-for-time compensation arrangement by a substitute physician or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area | GA | Waiver of liability statement issued as required by payer policy, individual case | GC | This service has been performed in part by a resident under the direction of a teaching physician | 23 | Unusual anesthesia: occasionally, a procedure, which usually requires either no anesthesia or local anesthesia, because of unusual circumstances must be done under general anesthesia. this circumstance may be reported by adding modifier 23 to the procedure code of the basic service. | CR | Catastrophe/disaster related | 53 | Discontinued procedure: under certain circumstances, the physician or other qualified health care professional may elect to terminate a surgical or diagnostic procedure. due to extenuating circumstances or those that threaten the well being of the patient, it may be necessary to indicate that a surgical or diagnostic procedure was started but discontinued. this circumstance may be reported by adding modifier 53 to the code reported by the individual for the discontinued procedure. note: this modifier is not used to report the elective cancellation of a procedure prior to the patient's anesthesia induction and/or surgical preparation in the operating suite. for outpatient hospital/ambulatory surgery center (asc) reporting of a previously scheduled procedure/service that is partially reduced or cancelled as a result of extenuating circumstances or those that threaten the well being of the patient prior to or after administration of anesthesia, see modifiers 73 and 74 (see modifiers approved for asc hospital outpatient use). | AQ | Physician providing a service in an unlisted health professional shortage area (hpsa) | X5 | Diagnostic services requested by another clinician: for reporting services by a clinician who furnishes care to the patient only as requested by another clinician or subsequent and related services requested by another clinician; this modifier is reported for patient relationships that may not be adequately captured by the above alternative categories; reporting clinician service examples include but are not limited to, the radiologist's interpretation of an imaging study requested by another clinician | 22 | Increased procedural services: when the work required to provide a service is substantially greater than typically required, it may be identified by adding modifier 22 to the usual procedure code. documentation must support the substantial additional work and the reason for the additional work (ie, increased intensity, time, technical difficulty of procedure, severity of patient's condition, physical and mental effort required). note: this modifier should not be appended to an e/m service. | 33 | Preventive services: when the primary purpose of the service is the delivery of an evidence based service in accordance with a us preventive services task force a or b rating in effect and other preventive services identified in preventive services mandates (legislative or regulatory), the service may be identified by adding 33 to the procedure. for separately reported services specifically identified as preventive, the modifier should not be used. | 52 | Reduced services: under certain circumstances a service or procedure is partially reduced or eliminated at the discretion of the physician or other qualified health care professional. under these circumstances the service provided can be identified by its usual procedure number and the addition of modifier 52, signifying that the service is reduced. this provides a means of reporting reduced services without disturbing the identification of the basic service. note: for hospital outpatient reporting of a previously scheduled procedure/service that is partially reduced or cancelled as a result of extenuating circumstances or those that threaten the well-being of the patient prior to or after administration of anesthesia, see modifiers 73 and 74 (see modifiers approved for asc hospital outpatient use). | 58 | Staged or related procedure or service by the same physician or other qualified health care professional during the postoperative period: it may be necessary to indicate that the performance of a procedure or service during the postoperative period was: (a) planned or anticipated (staged); (b) more extensive than the original procedure; or (c) for therapy following a surgical procedure. this circumstance may be reported by adding modifier 58 to the staged or related procedure. note: for treatment of a problem that requires a return to the operating/procedure room (eg, unanticipated clinical condition), see modifier 78. | 59 | Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25. | 74 | Discontinued out-patient hospital/ambulatory surgery center (asc) procedure after administration of anesthesia: due to extenuating circumstances or those that threaten the well being of the patient, the physician may terminate a surgical or diagnostic procedure after the administration of anesthesia (local, regional block(s), general) or after the procedure was started (incision made, intubation started, scope inserted, etc). under these circumstances, the procedure started but terminated can be reported by its usual procedure number and the addition of modifier 74. note: the elective cancellation of a service prior to the administration of anesthesia and/or surgical preparation of the patient should not be reported. for physician reporting of a discontinued procedure, see modifier 53. | 76 | Repeat procedure or service by same physician or other qualified health care professional: it may be necessary to indicate that a procedure or service was repeated by the same physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 76 to the repeated procedure or service. note: this modifier should not be appended to an e/m service. | 77 | Repeat procedure by another physician or other qualified health care professional: it may be necessary to indicate that a basic procedure or service was repeated by another physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 77 to the repeated procedure or service. note: this modifier should not be appended to an e/m service. | 78 | Unplanned return to the operating/procedure room by the same physician or other qualified health care professional following initial procedure for a related procedure during the postoperative period: it may be necessary to indicate that another procedure was performed during the postoperative period of the initial procedure (unplanned procedure following initial procedure). when this procedure is related to the first, and requires the use of an operating/procedure room, it may be reported by adding modifier 78 to the related procedure. (for repeat procedures, see modifier 76.) | 79 | Unrelated procedure or service by the same physician or other qualified health care professional during the postoperative period: the individual may need to indicate that the performance of a procedure or service during the postoperative period was unrelated to the original procedure. this circumstance may be reported by using modifier 79. (for repeat procedures on the same day, see modifier 76.) | 93 | Synchronous telemedicine service rendered via telephone or other real-time interactive audio-only telecommunications system : synchronous telemedicine service is defined as a real-time interaction between a physician or other qualified health care professional and a patient who is located away at a distant site from the physician or other qualified health care professional. the totality of the communication of information exchanged between the physician or other qualified health care professional and the patient during the course of the synchronous telemedicine service must be of an amount and nature that is sufficient to meet the key components and/or requirements of the same service when rendered via a face-to-face interaction. | 99 | Multiple modifiers: under certain circumstances 2 or more modifiers may be necessary to completely delineate a service. in such situations modifier 99 should be added to the basic procedure, and other applicable modifiers may be listed as part of the description of the service. | A6 | Dressing for six wounds | CC | Procedure code change (use 'cc' when the procedure code submitted was changed either for administrative reasons or because an incorrect code was filed) | CS | Cost-sharing waived for specified covid-19 testing-related services that result in and order for or administration of a covid-19 test and/or used for cost-sharing waived preventive services furnished via telehealth in rural health clinics and federally qualified health centers during the covid-19 public health emergency | ET | Emergency services | FS | Split (or shared) evaluation and management visit | G8 | Monitored anesthesia care (mac) for deep complex, complicated, or markedly invasive surgical procedure | GE | This service has been performed by a resident without the presence of a teaching physician under the primary care exception | GT | Via interactive audio and video telecommunication systems | GV | Attending physician not employed or paid under arrangement by the patient's hospice provider | GW | Service not related to the hospice patient's terminal condition | GY | Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit | GZ | Item or service expected to be denied as not reasonable and necessary | KL | Dmepos item delivered via mail | KS | Glucose monitor supply for diabetic beneficiary not treated with insulin | KX | Requirements specified in the medical policy have been met | LT | Left side (used to identify procedures performed on the left side of the body) | P5 | A moribund patient who is not expected to survive without the operation | PL | Progressive addition lenses | Q0 | Investigational clinical service provided in a clinical research study that is in an approved clinical research study | Q1 | Routine clinical service provided in a clinical research study that is in an approved clinical research study | Q3 | Live kidney donor surgery and related services | Q5 | Service furnished under a reciprocal billing arrangement by a substitute physician or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area | QA | Prescribed amounts of stationary oxygen for daytime use while at rest and nighttime use differ and the average of the two amounts is less than 1 liter per minute (lpm) | QJ | Services/items provided to a prisoner or patient in state or local custody, however the state or local government, as applicable, meets the requirements in 42 cfr 411.4 (b) | Ordering professional consulted a qualified clinical decision support mechanism for this service and the related data was provided to the furnishing professional | RT | Right side (used to identify procedures performed on the right side of the body) | SA | Nurse practitioner rendering service in collaboration with a physician | T1 | Left foot, second digit | TP | Medical transport, unloaded vehicle | U1 | Medicaid level of care 1, as defined by each state | U2 | Medicaid level of care 2, as defined by each state | XE | Separate encounter, a service that is distinct because it occurred during a separate encounter | XU | Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service |
|
Date
|
Action
|
Notes
|
|---|---|---|
| 2018-01-01 | Added | Code Added. |
Get instant expert-level medical coding assistance.