Summary & Overview
CPT 91117: Colonic Motility Study (Colon Manometry)
CPT code 91117 represents a colonic motility study (manometry) in which the provider evaluates the motor activity of the large intestine by measuring muscle contraction strength across physiologic states and after provocative stimulation. This functional test is clinically important for diagnosing disorders of colonic transit and motility, guiding management of chronic constipation, fecal incontinence, and other neurogastroenterology conditions. Nationally, accurate coding and coverage determination for 91117 affect access to specialized diagnostic testing and appropriate care pathways for patients with complex bowel dysfunction.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the procedure, typical sites of service, and the clinical context in which the test is used. The publication provides benchmark perspectives and policy-relevant considerations around coverage and utilization, along with coding details necessary for billing teams and clinicians. Practical sections cover common modifiers and expected service line placement where available. Data not available in the input is noted where applicable.
Billing Code Overview
CPT code 91117 describes a diagnostic procedure in which the provider accesses the colon (large intestine) to measure the strength and pattern of colonic muscle contractions. The study records motor activity of the colon at rest, during sleep, on awakening, following meals, and after provocative stimuli such as pharmacologic agents or balloon distensions.
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Service type: Colonic motility study (manometry) assessing motor function of the large intestine
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Typical site of service: Gastroenterology procedure suite or hospital endoscopy/functional testing unit
Clinical & Coding Specifications
Clinical Context
A 45-year-old patient with chronic, unexplained constipation and intermittent abdominal pain is referred to a gastroenterologist after standard evaluations including colonoscopy and abdominal imaging are unrevealing. The clinician schedules a colonic manometry study to evaluate colonic motor function. The procedure involves endoscopic placement of a manometry catheter into the colon or placement via an existing stoma, monitoring resting and sleep motor activity, and provoking responses with meals, waking, pharmacologic agents (e.g., neostigmine), or controlled balloon distension. The clinical workflow includes pre-procedure consent and bowel preparation, insertion of the manometry catheter (often during a colonoscopy or under fluoroscopic guidance), prolonged monitoring in an outpatient ambulatory unit or inpatient setting, documentation of baseline and provoked motility patterns, interpretation by the gastroenterologist, and a diagnostic report guiding management for colonic inertia, pseudo-obstruction, or refractory slow-transit constipation.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier reported | General placeholder; not typically appended by providers |
11 | Primary service | When 91117 is the primary procedure on the claim |
22 | Increased procedural services | When work or resources substantially exceed usual for 91117 (extensive monitoring or prolonged study) |
23 | Unusual anesthesia | If the procedure requires anesthesia for medically necessary reasons beyond typical sedation |
26 | Professional component | When billing separately for physician interpretation/report of the manometry tracing |
52 | Reduced services | If the study was started but not completed or shortened without full protocol completion |
53 | Discontinued procedure | If the study was abandoned for patient safety reasons and documentation supports discontinuation |
78 | Return to OR/procedure following initial procedure | If a repeat catheter placement is required intra-procedure due to dislodgement or complication during same operative session |
80 | Assistant surgeon | When a qualified assistant surgeon participates in the catheter placement during an operative session |
82 | Assistant surgeon when qualified resident not available | When an assistant is required and a qualified resident is not available |
AS | Physician assistant, nurse practitioner, or clinical nurse specialist services | When such advanced practice clinicians perform portions of the service as allowed by payor policy |
TC | Technical component | When billing only for the technical acquisition of the manometry recordings (facility/technical services) |
QK | Medical direction of two, three, or four concurrent anesthesia procedures | If anesthesia direction is billed for concurrent anesthesia tasks during catheter placement |
QX | CRNA service with medical direction | When a certified registered nurse anesthetist provides anesthesia under medical direction |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 207RC0000X | Gastroenterology | Primary specialty performing colonic manometry and interpretation |
| 207RH0000X | Pediatric Gastroenterology | Pediatric patients with motility disorders may require this study |
| 363L00000X | Registered Nurse Anesthetist | Provides monitored anesthesia care when needed during placement |
| 208D00000X | General Surgery | Surgeons may place catheters intraoperatively or manage related complications |
| 261QM0800X | Physician Assistant | May assist in procedure setup, monitoring, and documentation |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
K59.0 | Constipation | Common indication for colonic manometry to evaluate slow-transit constipation and colonic inertia |
K59.1 | Functional diarrhea | Differentiation of motility patterns may be relevant when mixed bowel symptoms occur |
K59.2 | Neurogenic bowel, not elsewhere classified | Colonic motility testing can assess dysfunction related to neurologic disease |
K56.7 | Ileus, unspecified | Manometry helps distinguish mechanical obstruction from severe motility failure in selected cases |
R10.9 | Abdominal pain, unspecified | Chronic unexplained abdominal pain may prompt motility testing when other workup is unrevealing |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
44388 | Colonoscopy, flexible; with removal of foreign body | Colonoscopy may be used to place a manometry catheter or to evaluate findings prior to 91117 |
43453 | Esophageal manometry (high-resolution) — diagnostic | Analagous motility study workflow; referenced for interpretation standards though different organ system |
91110 | Anal manometry, anorectal manometry; diagnostic | Often performed in conjunction when evaluating defecatory disorders alongside 91117 |
96372 | Therapeutic, prophylactic, or diagnostic injection (e.g., medication administration) | Used when pharmacologic provocation (e.g., neostigmine) is administered during the study |
51784 | Bladder manometry | Other regional physiologic pressure monitoring studies sometimes co-ordered in complex pelvic floor dysfunction evaluations |