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Official Description

Complex cystometrogram (ie, calibrated electronic equipment); with voiding pressure studies (ie, bladder voiding pressure), any technique

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

A complex cystometrogram (CMG) is a diagnostic procedure utilized to assess bladder function by measuring bladder capacity and storage pressures. This test is particularly important for evaluating various urological conditions, including urinary incontinence, difficulties with urination, and neurogenic bladder disorders. The procedure begins with the patient emptying their bladder, after which the volume of urine is measured. To ensure a sterile environment, the urethra is cleansed with an antiseptic solution. A sterile catheter equipped with a sensor is then carefully inserted through the urethra into the bladder. Once in place, the bladder is filled with sterile saline, and the physician engages the patient in a dialogue to gauge their sensations during the filling process, including feelings of fullness, pain, urgency, and any involuntary leakage. The complex CMG, as indicated by CPT® Code 51728, employs calibrated electronic equipment to provide precise measurements of intra-abdominal pressure, total bladder pressure, and true detrusor pressure simultaneously. The detrusor muscle is the primary muscle responsible for bladder contraction. This advanced technique allows for the differentiation between involuntary detrusor contractions and changes in bladder compliance that may occur due to increased intra-abdominal pressure. The procedure may also include voiding pressure studies, where the bladder is filled with fluid, and the patient is prompted to void. During this phase, various pressures are recorded, including those prior to voiding, sphincter opening pressure, maximum voiding pressure, and flow rates during bladder contractions. Multiple bladder fills may be necessary to obtain accurate evaluations of bladder voiding pressure. Following the completion of the complex CMG and any additional studies, the physician interprets the results and generates a comprehensive written report detailing the findings.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The complex cystometrogram (CMG) is indicated for the evaluation of various urological conditions. The following are the specific indications for performing this procedure:

  • Urinary Incontinence - Assessment of involuntary leakage of urine, which may be due to various underlying causes.
  • Difficulty with Urination - Evaluation of patients experiencing challenges in initiating or maintaining urination.
  • Neurogenic Bladder - Investigation of bladder dysfunction resulting from neurological conditions affecting bladder control.

2. Procedure

The procedure for a complex cystometrogram with voiding pressure studies involves several detailed steps to ensure accurate measurement and evaluation of bladder function:

  • Step 1: Patient Preparation - The patient is instructed to empty their bladder completely before the procedure begins. The volume of urine is measured to establish a baseline.
  • Step 2: Urethral Cleansing - The urethra is cleansed with an antiseptic solution to minimize the risk of infection during catheter insertion.
  • Step 3: Catheter Insertion - A sterile catheter equipped with a pressure sensor is carefully inserted through the urethra into the bladder. This catheter is essential for measuring bladder pressures during the procedure.
  • Step 4: Bladder Filling - The bladder is filled with sterile saline solution. This step is crucial for assessing bladder capacity and the pressures experienced during filling.
  • Step 5: Patient Sensation Assessment - Throughout the filling process, the physician queries the patient regarding their sensations, including feelings of fullness, pain, urgency, and any involuntary leakage.
  • Step 6: Voiding Pressure Studies - After the bladder is adequately filled, the patient is asked to void. During this phase, sensors record various pressures, including those prior to voiding, sphincter opening pressure, maximum voiding pressure, and flow rates during bladder contractions.
  • Step 7: Data Interpretation - The collected data is analyzed to evaluate bladder function, and multiple bladder fills may be performed to ensure accurate assessment of voiding pressures.

3. Post-Procedure

After the completion of the complex cystometrogram and voiding pressure studies, the physician interprets the results and compiles a written report detailing the findings. Patients may be monitored for any immediate post-procedure complications, and instructions regarding hydration and any potential follow-up appointments are provided. It is important for patients to report any unusual symptoms or discomfort following the procedure to their healthcare provider.

Short Descr CYSTOMETROGRAM W/VP
Medium Descr COMPLEX CYSTOMETROGRAM VOIDING PRESSURE STUDIES
Long Descr Complex cystometrogram (ie, calibrated electronic equipment); with voiding pressure studies (ie, bladder voiding pressure), any technique
Status Code Active Code
Global Days 000 - Endoscopic or Minor Procedure
PC/TC Indicator (26, TC) 1 - Diagnostic Tests for Radiology Services
Multiple Procedures (51) 2 - Standard payment adjustment rules for multiple 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) 0 - 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.
Diagnostic Imaging Family 99 - Concept Does Not Apply
APC Status Indicator Hospital Part B services paid through a comprehensive APC
ASC Payment Indicator Office-based surgical procedure added to ASC list in CY 2008 or later with MPFS nonfacility PE RVUs; payment based on MPFS nonfacility PE RVUs.
Type of Service (TOS) 2 - Surgery
Berenson-Eggers TOS (BETOS) P6C - Minor procedures - other (Medicare fee schedule)
MUE 1
CCS Clinical Classification 200 - Nonoperative urinary system measurements

This is a primary code that can be used with these additional add-on codes.

51797 Addon Code Resequenced Code MPFS Status: Active Code APC N ASC N1 CPT Assistant Article Illustration for Code Voiding pressure studies, intra-abdominal (ie, rectal, gastric, intraperitoneal) (List separately in addition to code for primary procedure)
26 Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number.
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).
TC Technical component; under certain circumstances, a charge may be made for the technical component alone; under those circumstances the technical component charge is identified by adding modifier 'tc' to the usual procedure number; technical component charges are institutional charges and not billed separately by physicians; however, portable x-ray suppliers only bill for technical component and should utilize modifier tc; the charge data from portable x-ray suppliers will then be used to build customary and prevailing profiles
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).
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
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.
GA Waiver of liability statement issued as required by payer policy, individual case
CR Catastrophe/disaster related
AQ Physician providing a service in an unlisted health professional shortage area (hpsa)
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.)
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
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.
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).
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.)
95 Synchronous telemedicine service rendered via a real-time interactive audio and video 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 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 would be sufficient to meet the key components and/or requirements of the same service when rendered via a face-to-face interaction. modifier 95 may only be appended to the services listed in appendix p. appendix p is the list of cpt codes for services that are typically performed face-to-face, but may be rendered via a real-time (synchronous) interactive audio and video telecommunications system.
AG Primary physician
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)
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
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
Q1 Routine clinical service provided in a clinical research study that is in an approved clinical research study
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
SA Nurse practitioner rendering service in collaboration with a physician
SG Ambulatory surgical center (asc) facility service
SU Procedure performed in physician's office (to denote use of facility and equipment)
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
XS Separate structure, a service that is distinct because it was performed on a separate organ/structure
Date
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2010-01-01 Added -
1984-12-31 Deleted Code deleted.
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