🧬 ICD-10 CM K80.50 — Calculus Of Bile Duct Without Cholangitis Or Cholecystitis Without Obstruction
Billable Code Confirmed
ICD-10 CM K80.50 carries five significant characters (K, 8, 0, 5, 0) and is fully billable for FY2026 (effective 10/1/2025). The fifth character (0) specifically documents the absence of obstruction, distinguishing this from its sibling K80.51, which requires the sixth character for the obstructed variant.
Non-Billable Parent Codes
K80 (Cholelithiasis) is the category header and carries no billing specificity on its own — it requires a full breakdown by gallbladder/bile duct involvement, cholecystitis status, and obstruction status before it can be reported. K80.5 (Calculus of bile duct without cholangitis or cholecystitis) is a non-billable subcategory that still lacks the sixth character needed to specify obstruction status, so it will reject on any HIPAA-covered claim.
Clinical Context
The clinical distinction driving code selection is twofold: whether the gallbladder itself is inflamed (cholecystitis) or the bile duct is infected (cholangitis) — neither is present here — and whether the stone is causing obstruction. K80.50 is reserved for a documented bile duct stone with no obstruction, no cholangitis, and no cholecystitis, which is the presentation most often picked up incidentally on imaging or during an unrelated workup.
Code Classification
This is a diagnosis code (ICD-10-CM), not a procedure code. It reports the clinical condition only; any intervention performed to remove or manage the stone (ERCP, choledochotomy, laparoscopic exploration) must be reported separately using the appropriate CPT or ICD-10-PCS code.
🔍 Code Description
ICD-10 CM K80.50 describes a calculus lodged within the bile duct — most often the common bile duct — in a patient who has no concurrent cholangitis (duct infection) and no concurrent cholecystitis (gallbladder inflammation), and in whom the stone is not causing mechanical obstruction of bile flow. This presentation is frequently discovered incidentally, for example on an intraoperative cholangiogram during an otherwise routine 47564 laparoscopic cholecystectomy, or on cross-sectional imaging obtained for an unrelated complaint, since the absence of obstruction often means the patient is minimally symptomatic or has only intermittent biliary colic.
Because the stone is not obstructing, liver enzymes and bilirubin are typically normal or only mildly elevated, which clinically distinguishes this presentation from K80.51 (the same stone with obstruction, which produces jaundice, elevated alkaline phosphatase, and dilated ducts on imaging). Documentation should clearly state “without obstruction” or reflect normal duct caliber and labs, since silence on obstruction status is not the same as ruling it out — an undocumented obstruction status should prompt a physician query rather than a default assumption of K80.50.
🌳 Code Tree / Hierarchy
K80 Cholelithiasis ❌ Non-billable
│
├── K80.0 Calculus of gallbladder with acute cholecystitis ❌ Non-billable
│ │
│ ├── K80.00 …with acute cholecystitis without obstruction ✅ Billable
│ └── K80.01 …with acute cholecystitis with obstruction ✅ Billable
│
├── K80.5 Calculus of bile duct without cholangitis or cholecystitis ❌ Non-billable
│ │
│ ├── K80.50 …without obstruction ◀ THIS CODE ✅ Billable
│ └── K80.51 …with obstruction ✅ Billable
│
└── K80.6 Calculus of gallbladder and bile duct with cholecystitis ❌ Non-billable
│
├── K80.66 …with acute and chronic cholecystitis without obstruction ✅ Billable
└── K80.67 …with acute and chronic cholecystitis with obstruction ✅ BillableWhy Obstruction Status Drives the Code
Selecting K80.50 over K80.51 matters for medical necessity documentation on any ERCP prior authorization — payers scrutinize whether imaging or labs actually support “without obstruction,” and downcoding an obstructed stone to K80.50 can trigger a denial for lack of medical necessity on the therapeutic ERCP that follows.
Tip
Always confirm the gallbladder’s own status separately — a patient can have a documented bile duct stone (K80.5x) with a completely normal, non-inflamed gallbladder still in place, which is a different clinical and coding picture than the combined gallbladder-and-duct calculus codes in the K80.6x/K80.7x families.
✅ Includes
- Choledocholithiasis — the general clinical term for any stone within the bile duct system; K80.50 applies to the uncomplicated, non-obstructing form.
- Hepatic colic (recurrent), without cholangitis or cholecystitis — intermittent biliary-type pain from a duct stone that is not currently obstructing flow.
- Common bile duct stone without obstruction — the most common lay/clinical phrasing coders will encounter in operative notes and imaging reports for this exact code.
❌ Excludes
Excludes 1
Danger
The most common Excludes1 error here is coding a post-cholecystectomy retained duct stone to K80.50 out of habit because the clinical presentation (biliary colic, incidental duct stone on ERCP) looks identical. Always check the surgical history first — a prior cholecystectomy redirects the code to K91.86, not K80.50.
Excludes 2
No Excludes2 notes are documented at the K80.50 code level in the FY2026 Tabular List; check the K80 category and K80.5- subcategory levels directly in your current code book, as annotation coverage can shift with quarterly updates.
📋 Clinical Overview
Obstruction Status Comparison
The defining clinical variable across this code family is whether the stone is actually blocking bile flow, which changes both the presenting picture and the urgency of intervention.
| Feature | K80.50 | K80.51 | K80.66 |
|---|---|---|---|
| Obstruction | Absent — normal bile flow | Present — mechanical blockage | Absent, with cholecystitis also present |
| Typical labs | Normal or mildly elevated LFTs | Elevated bilirubin, alkaline phosphatase | Elevated inflammatory markers, variable LFTs |
| Urgency | Often elective workup or incidental finding | Requires timely ERCP to relieve obstruction | Requires cholecystectomy; duct stone addressed concurrently |
Important
A CDI trigger phrase here is any mention of “dilated common bile duct,” “elevated bilirubin,” or “jaundice” alongside a bile duct stone — these findings point to obstruction and should prompt a query to confirm K80.51 instead of K80.50 if the documentation doesn’t explicitly rule obstruction in or out.
Manifestations & Symptom Burden
- Biliary colic — episodic right-upper-quadrant or epigastric pain, often postprandial, from transient duct irritation without full obstruction.
- Incidental imaging finding — many K80.50 cases are asymptomatic and discovered on ultrasound, CT, or intraoperative cholangiogram performed for another reason.
- Mild nausea — nonspecific and may or may not be documented; not required to support the code.
Tip
Asymptomatic incidental stones still support K80.50 as long as the stone itself is documented by the provider as a diagnosis being addressed or monitored — an image finding alone, without provider acknowledgment in the assessment/plan, is not sufficient to code.
💰 HCC Risk Adjustment
| Model | Maps to HCC? | RAF Impact |
|---|---|---|
| CMS-HCC v28 | No | None |
| CMS-HCC v24 | No | None |
ICD-10 CM K80.50 does not carry risk-adjustment weight under current CMS-HCC models because uncomplicated choledocholithiasis is treated as an acute, resolvable condition rather than a chronic illness burden. There is no annual capture requirement for this code, and its absence from a claim in a subsequent year does not affect a patient’s risk score — this is worth knowing so coders don’t spend query effort chasing HCC capture on a code that carries none.
🏥 MS-DRG Assignment
| DRG | Title | Relative Weight | GMLOS |
|---|---|---|---|
| 444 | Disorders of Biliary Tract with MCC | Varies by FY43.0 table | Varies |
| 445 | Disorders of Biliary Tract with CC | Varies by FY43.0 table | Varies |
| 446 | Disorders of Biliary Tract without CC/MCC | 0.8273 | 2.10 |
When K80.50 is principal diagnosis and no OR procedure is performed, the claim groups medically to DRG 444/445/446 based purely on secondary-diagnosis CC/MCC status. If an ERCP, choledochotomy, or laparoscopic exploration is performed in the same stay, the claim instead groups surgically under the biliary tract procedure partition of MDC 07, which generally carries a higher weight — sequencing the procedure code correctly is what actually drives reimbursement here, not the diagnosis alone.
- NCD/LCD note: There is no national coverage determination (NCD) specific to choledocholithiasis or its associated ERCP/duct-exploration procedures — coverage is determined by medical necessity documentation at the local level.
- Noridian’s non-covered services LCDs (L36219 for JE, L35008 for JF) do not list standard ERCP stone-extraction codes (43264, 43265) as non-covered; they instead flag specific add-on/emerging technology codes (e.g., 0397T optical endomicroscopy during ERCP) as investigational, so confirm any newer add-on code against the current non-covered services list before billing it alongside a standard ERCP.
🔗 Related ICD-10-CM Codes
Group 1 — Sibling Calculus-of-Bile-Duct Codes
- K80.51 — Calculus of bile duct without cholangitis or cholecystitis, with obstruction
- K80.66 — Calculus of gallbladder and bile duct with acute and chronic cholecystitis without obstruction
- K80.67 — Calculus of gallbladder and bile duct with acute and chronic cholecystitis with obstruction
- K80.70 — Calculus of gallbladder and bile duct without cholecystitis without obstruction
- K80.71 — Calculus of gallbladder and bile duct without cholecystitis with obstruction
Group 2 — Related Hepatobiliary Complications
- K83.1 — Obstruction of bile duct (use when obstruction exists without a documented calculus as the cause)
- K85.10 — Biliary acute pancreatitis without necrosis or infection (code first if pancreatitis is the acute process being treated)
- K91.86 — Retained cholelithiasis following cholecystectomy (mutually exclusive per Excludes1 above)
🛠️ Commonly Associated CPT Codes
| CPT Code | Billing Note |
|---|---|
| 43260 | Diagnostic ERCP with specimen collection; used if the stone is confirmed but no therapeutic intervention is performed in the same session. |
| 43262 | ERCP with sphincterotomy/papillotomy; commonly performed to widen the ampulla before stone extraction. |
| 43264 | ERCP with removal of calculi/debris from the bile duct — the primary therapeutic code for an uncomplicated K80.50 stone. |
| 43265 | ERCP with destruction of calculi by mechanical, electrohydraulic, or lithotripsy method; used for larger or harder stones that resist standard basket/balloon extraction. |
| 47420 | Open choledochotomy with exploration, drainage, or removal of calculus; reserved for cases where ERCP fails or is not feasible. |
| 47564 | Laparoscopic cholecystectomy with exploration of the common duct; appropriate when the gallbladder is being removed concurrently even though it is not itself diseased. |
| 74300 | Intraoperative cholangiography, radiological supervision and interpretation; frequently the study that incidentally identifies the K80.50 stone in the first place. |
🏷️ Modifier Reference
| Modifier | Name | When to Apply |
|---|---|---|
| -59 | Distinct Service | Applies when a bile duct procedure is performed on a separate structure or session from another same-day procedure that would otherwise appear bundled. |
| -51 | Multiple Procedures | Applies when an ERCP-based procedure (e.g., sphincterotomy plus stone removal) is billed alongside another significant procedure in the same session. |
| -52 | Reduced Services | Applies if an ERCP is attempted but a planned component (e.g., full duct clearance) is not completed due to anatomic difficulty, without meeting discontinued-procedure criteria. |
| -53 | Discontinued | Applies if the ERCP or surgical exploration is stopped after anesthesia induction due to patient risk, before the procedure is completed. |
| -58 | Staged | Applies when a planned second-stage procedure (e.g., a later ERCP to complete duct clearance) occurs within the global period of an earlier related procedure. |
| -78 | Return to OR | Applies when the patient returns to the OR for a related complication (e.g., bile leak) during the global period of the original procedure. |
| -79 | Unrelated Procedure | Applies when an unrelated procedure is performed during the global period of a prior, unrelated surgery. |
| -25 | Significant E/M | Applies when a significant, separately identifiable E/M service is documented on the same day as the ERCP or biliary procedure. |
| -24 | Unrelated E/M | Applies when an E/M service unrelated to the biliary procedure occurs during that procedure’s global period. |
NCCI Bundling Considerations
Diagnostic ERCP (43260) is bundled into any therapeutic ERCP performed in the same session (43262, 43264, 43265) under NCCI PTP edits, so only the highest-level therapeutic code should be billed unless a bundling-override modifier is clinically supported and documented.
🔬 ICD-10-PCS Crosswalk
| PCS Code | Description |
|---|---|
| 0FC98ZZ | Extirpation of Matter from Common Bile Duct, Via Natural or Artificial Opening Endoscopic — the PCS equivalent of a therapeutic ERCP stone extraction performed inpatient. |
| 0FC94ZZ | Extirpation of Matter from Common Bile Duct, Percutaneous Endoscopic Approach — used when the duct is accessed percutaneously with endoscopic assistance rather than transorally. |
| 0FC90ZZ | Extirpation of Matter from Common Bile Duct, Open Approach — reported when the stone is removed via an open choledochotomy rather than endoscopically. |
💊 Coding Scenarios and Examples
Example 1
Clinical Scenario:
A patient admitted for an unrelated abdominal complaint undergoes a CT scan that incidentally reveals a common bile duct stone. Liver function tests are within normal limits and there is no evidence of ductal dilation. The attending documents the finding as an incidental, non-obstructing common bile duct stone and elects outpatient ERCP follow-up rather than intervening during this admission.
| Field | Code | Rationale |
|---|---|---|
| PDx | K80.50 | The stone is documented as non-obstructing with normal labs, and no cholangitis or cholecystitis is present. |
Tip
Because no procedure was performed during this admission, K80.50 is reported as a secondary diagnosis with the actual reason for admission sequenced as principal — never let an incidental finding become principal diagnosis unless it becomes the focus of treatment during the stay.
Example 2
Clinical Scenario:
A patient presents with intermittent right-upper-quadrant pain. Imaging confirms a non-obstructing common bile duct stone with a normal, non-inflamed gallbladder still in place. The gastroenterologist performs a diagnostic ERCP that confirms the stone, followed in the same session by sphincterotomy and basket extraction of the calculus.
| Field | Code | Rationale |
|---|---|---|
| CPT | 43264 | Therapeutic removal of the calculus is the highest-level ERCP service performed and bundles the diagnostic component. |
| CPT 2 | 43262 | Sphincterotomy performed to facilitate extraction is separately reportable alongside the stone removal per current CPT guidance. |
| PDx | K80.50 | Confirms the non-obstructing bile duct stone as the reason for the procedure. |
Tip
Diagnostic ERCP (43260) is not separately reported here since it is bundled into the therapeutic codes performed in the same session per NCCI edits. CDI note: if imaging or operative findings actually described ductal dilation, this scenario would shift to K80.51 — confirm obstruction status is explicitly ruled out before finalizing K80.50.
Example 3
Clinical Scenario:
A patient with a documented non-obstructing common bile duct stone undergoes a laparoscopic cholecystectomy for an unrelated symptomatic gallbladder, and the surgeon performs an intraoperative cholangiogram followed by laparoscopic common duct exploration to remove the incidentally confirmed stone in the same session.
| Field | Code | Rationale |
|---|---|---|
| CPT | 47564 | Laparoscopic cholecystectomy with common duct exploration captures both the gallbladder removal and the duct stone extraction in one code. |
| PDx | K80.50 | The bile duct stone remains non-obstructing and is coded independently of the gallbladder’s own condition. |
Tip
Sequencing depends on which condition is documented as the primary reason for admission — if the gallbladder disease prompted the admission, sequence that diagnosis first with K80.50 as secondary. CDI note: confirm the operative note explicitly documents “common duct exploration,” not just an intraoperative cholangiogram alone, since imaging without extraction does not support 47564’s exploration component.
⚠️ Coding Pitfalls and Tips
- Pitfall 1: Coding K80.5 or K80 directly on a claim without the required additional character(s), leading to an automatic rejection; Tips: Always encode to the full 4-character level (K80.50 or K80.51) — never stop at the category or subcategory header.
- Pitfall 2: Defaulting to K80.50 when obstruction status is simply not documented, rather than treating it as a query opportunity; Tips: Silence on obstruction is not equivalent to “without obstruction” — query the provider if labs or imaging don’t clearly settle the question.
- Pitfall 3: Coding a retained duct stone in a post-cholecystectomy patient to K80.50 instead of K91.86; Tips: Always check surgical history for a prior cholecystectomy before assigning any K80.5x code.
- Pitfall 4: Reporting diagnostic ERCP (43260) alongside a therapeutic ERCP code (43264/43265) performed in the same session; Tips: NCCI bundles the diagnostic component into the therapeutic code — bill only the highest-level service performed.
- Pitfall 5: Sequencing K80.50 as principal diagnosis when the actual admission was driven by a different, more acute condition (e.g., pancreatitis or an unrelated surgical issue) and the stone was only an incidental finding; Tips: Reserve principal diagnosis for the condition that occasioned the admission after study, per Uniform Hospital Discharge Data Set guidelines.
- Pitfall 6: Assuming this code carries HCC risk-adjustment weight and spending query effort chasing its annual capture; Tips: K80.50 is not HCC-mapped under current CMS-HCC models — direct risk-adjustment query effort toward chronic conditions instead.
📚 Sources
1. icd10data.com. *K80.50 — Calculus of bile duct without cholangitis or cholecystitis without obstruction.* 2026 ICD-10-CM, effective 10/1/2025. 2. icd10data.com. *K80.51 — Calculus of bile duct without cholangitis or cholecystitis with obstruction.* 2026 ICD-10-CM, effective 10/1/2025. 3. icd10data.com. *K80 / K80.5 — Cholelithiasis category and subcategory Excludes1 annotations.* 2026 ICD-10-CM. 4. icdlist.com. *DRG 446 — Disorders of the Biliary Tract without CC/MCC, MS-DRG v43.0.* Effective 10/1/2025–9/30/2026. 5. icd10data.com. *K83.1 — Obstruction of bile duct; K85.1/K85.10 — Biliary acute pancreatitis.* 2026 ICD-10-CM. 6. icdlist.com / icd10data.com. *0FC9 table — Extirpation of Matter from Common Bile Duct, ICD-10-PCS 2026.* 7. AAO/Noridian. *Local Coverage Determination (LCD): Non-Covered Services, L36219 (JE) / L35008 (JF).*Sources listed above correspond to superscript citations throughout this note. Verify all Medicare payment figures against your current CMS PFS Lookup tool and applicable MAC LCD prior to claim submission. Please use the latest AAPC/AHIMA Coding Books to verify each code within this note.