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Official Description

Sigmoidoscopy, flexible; with biopsy, single or multiple

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

A flexible sigmoidoscopy is a diagnostic procedure that allows for the examination of the lower part of the colon, specifically the sigmoid colon, using a flexible tube known as a sigmoidoscope. This procedure can be performed with or without the collection of specimens, which may include brushing or washing techniques as indicated in CPT® code 45330. In the case of CPT® code 45331, the procedure specifically involves the collection of single or multiple biopsies. During the procedure, the sigmoidoscope is carefully inserted into the anus and advanced through the rectum into the sigmoid colon. Air insufflation is utilized to expand the colon and separate the mucosal folds, allowing for a thorough inspection of the mucosal surfaces. Any abnormalities such as ulcerations, varices, bleeding sites, lesions, or strictures are noted during this examination. After the initial inspection, the endoscope is withdrawn, and a second inspection of the mucosal surfaces is conducted to ensure that no abnormalities are missed. If necessary, a brush can be introduced through the endoscope to collect cytology samples, or sterile water may be used to wash the mucosal lining, with the fluid then aspirated to obtain cell samples. In the context of CPT® code 45331, any suspicious areas identified for biopsy are targeted, and biopsy forceps are introduced through the endoscope's biopsy channel. The forceps are then opened to capture tissue samples, which are subsequently removed through the endoscope. This procedure allows for the collection of one or more tissue samples, which are then sent for laboratory analysis to aid in diagnosis and treatment planning.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The flexible sigmoidoscopy with biopsy, as described in CPT® code 45331, is indicated for various clinical scenarios where direct visualization and tissue sampling of the sigmoid colon are necessary. The following conditions may warrant this procedure:

  • Suspicious lesions - The presence of abnormal growths or lesions in the sigmoid colon that require further evaluation through biopsy.
  • Unexplained gastrointestinal symptoms - Patients presenting with symptoms such as rectal bleeding, unexplained abdominal pain, or changes in bowel habits may be evaluated using this procedure.
  • Monitoring of known conditions - Patients with a history of inflammatory bowel disease or colorectal cancer may require regular surveillance to monitor for disease progression or recurrence.
  • Polyps - The identification and biopsy of polyps in the sigmoid colon for histological examination to determine their nature.

2. Procedure

The procedure for flexible sigmoidoscopy with biopsy involves several key steps that ensure a thorough examination and accurate tissue sampling. The following procedural steps are outlined:

  • Step 1: Preparation - The patient is positioned appropriately, typically in a left lateral position, to facilitate access to the rectum and sigmoid colon. Adequate bowel preparation is essential to ensure clear visualization during the procedure.
  • Step 2: Insertion of the sigmoidoscope - A standard flexible sigmoidoscope is gently inserted into the anus and advanced through the rectum into the sigmoid colon. Care is taken to navigate the curves of the colon while minimizing discomfort for the patient.
  • Step 3: Air insufflation - Air is insufflated through the sigmoidoscope to expand the colon, allowing for better visualization of the mucosal surfaces. This step is crucial for separating the mucosal folds and identifying any abnormalities.
  • Step 4: Inspection of mucosal surfaces - The mucosal surfaces of the sigmoid colon are meticulously inspected for any signs of abnormalities, including ulcerations, varices, bleeding sites, lesions, or strictures. Any findings are documented for further analysis.
  • Step 5: Withdrawal and re-inspection - The sigmoidoscope is then withdrawn slightly, and a second inspection of the mucosal surfaces is performed to ensure that no abnormalities are overlooked.
  • Step 6: Collection of cytology samples - If indicated, a brush may be introduced through the endoscope to collect cytology samples. Alternatively, sterile water can be used to wash the mucosal lining, and the aspirated fluid can be analyzed for cellular content.
  • Step 7: Biopsy procedure - In cases where suspicious sites are identified, biopsy forceps are introduced through the biopsy channel of the endoscope. The forceps are opened to capture tissue samples from the targeted area, and once the tissue is secured, the forceps are closed and withdrawn, bringing the biopsied tissue out through the endoscope.
  • Step 8: Sample handling - The collected tissue samples are then prepared for laboratory analysis, which may involve separate reporting depending on the laboratory's requirements.

3. Post-Procedure

After the flexible sigmoidoscopy with biopsy, patients are typically monitored for a short period to ensure there are no immediate complications, such as bleeding or perforation. It is common for patients to experience mild cramping or discomfort following the procedure due to air insufflation. Patients may be advised to rest and avoid strenuous activities for the remainder of the day. The results of the biopsy will be communicated to the patient once the laboratory analysis is complete, and any necessary follow-up appointments will be scheduled based on the findings. It is important for patients to report any unusual symptoms, such as significant abdominal pain or rectal bleeding, to their healthcare provider promptly.

Short Descr SIGMOIDOSCOPY AND BIOPSY
Medium Descr SIGMOIDOSCOPY FLX W/BIOPSY SINGLE/MULTIPLE
Long Descr Sigmoidoscopy, flexible; with biopsy, single or multiple
Status Code Active Code
Global Days 000 - Endoscopic or Minor Procedure
PC/TC Indicator (26, TC) 0 - Physician Service Code
Multiple Procedures (51) 3 - Special payment adjustment rules for multiple endoscopic procedures apply.
Bilateral Surgery (50) 0 - 150% payment adjustment for bilateral procedures does NOT apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 1 - Statutory payment restriction for assistants at surgery applies to this procedure...
Co-Surgeons (62) 0 - Co-surgeons not permitted for this procedure.
Team Surgery (66) 0 - Team surgeons not permitted for this procedure.
Endoscopic Base Code 45330  Sigmoidoscopy, flexible; diagnostic, including collection of specimen(s) by brushing or washing, when performed (separate procedure)
Diagnostic Imaging Family 99 - Concept Does Not Apply
APC Status Indicator Procedure or Service, Multiple Reduction Applies
ASC Payment Indicator Surgical procedure on ASC list in CY 2007; payment based on OPPS relative payment weight.
Type of Service (TOS) 2 - Surgery
Berenson-Eggers TOS (BETOS) P8C - Endoscopy - sigmoidoscopy
MUE 1
CCS Clinical Classification 77 - Proctoscopy and anorectal biopsy
51 Multiple procedures: when multiple procedures, other than e/m services, physical medicine and rehabilitation services or provision of supplies (eg, vaccines), are performed at the same session by the same individual, the primary procedure or service may be reported as listed. the additional procedure(s) or service(s) may be identified by appending modifier 51 to the additional procedure or service code(s). note: this modifier should not be appended to designated "add-on" codes (see appendix d).
PT Colorectal cancer screening test; converted to diagnostic test or other procedure
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.
GC This service has been performed in part by a resident under the direction of a teaching physician
GA Waiver of liability statement issued as required by payer policy, individual case
SG Ambulatory surgical center (asc) facility service
XS Separate structure, a service that is distinct because it was performed on a separate organ/structure
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.
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.
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).
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).
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.
73 Discontinued out-patient hospital/ambulatory surgery center (asc) procedure prior to the administration of anesthesia: due to extenuating circumstances or those that threaten the well being of the patient, the physician may cancel a surgical or diagnostic procedure subsequent to the patient's surgical preparation (including sedation when provided, and being taken to the room where the procedure is to be performed), but prior to the administration of anesthesia (local, regional block(s) or general). under these circumstances, the intended service that is prepared for but cancelled can be reported by its usual procedure number and the addition of modifier 73. 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.
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.)
80 Assistant surgeon: surgical assistant services may be identified by adding modifier 80 to the usual procedure number(s).
82 Assistant surgeon (when qualified resident surgeon not available): the unavailability of a qualified resident surgeon is a prerequisite for use of modifier 82 appended to the usual procedure code number(s).
AG Primary physician
AQ Physician providing a service in an unlisted health professional shortage area (hpsa)
AS Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery
CC Procedure code change (use 'cc' when the procedure code submitted was changed either for administrative reasons or because an incorrect code was filed)
CR Catastrophe/disaster related
FS Split (or shared) evaluation and management visit
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
GZ Item or service expected to be denied as not reasonable and necessary
KX Requirements specified in the medical policy have been met
PD Diagnostic or related non diagnostic item or service provided in a wholly owned or operated entity to a patient who is admitted as an inpatient within 3 days
PO Excepted service provided at an off-campus, outpatient, provider-based department of a hospital
Q1 Routine clinical service provided in a clinical research study that is in an approved clinical research study
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
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
RT Right side (used to identify procedures performed on the right side of the body)
UA Medicaid level of care 10, as defined by each state
X2 Continuous/focused services: for reporting services by clinicians whose expertise is needed for the ongoing management of a chronic disease or a condition that needs to be managed and followed with no planned endpoint to the relationship; reporting clinician service examples include but are not limited to: a rheumatologist taking care of the patient's rheumatoid arthritis longitudinally but not providing general primary care services
X3 Episodic/broad services: for reporting services by clinicians who have broad responsibility for the comprehensive needs of the patient that is limited to a defined period and circumstance such as a hospitalization; reporting clinician service examples include but are not limited to the hospitalist's services rendered providing comprehensive and general care to a patient while admitted to the hospital
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
XE Separate encounter, a service that is distinct because it occurred during a separate encounter
XP Separate practitioner, a service that is distinct because it was performed by a different practitioner
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
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