ICD code K80.50 – Bile duct calculus without obstruction

Key Takeaways

ICD-10 code K80.50 describes a bile duct stone with no cholangitis, no cholecystitis, and no obstruction, making the absence of all three the essential coding condition.

K80.51 is the adjacent code when obstruction is present. Elevated bilirubin, dilated CBD on imaging, or elevated ALP/GGT pushes the code from K80.50 to K80.51.

The most common claim denial for K80.50 is a missing imaging report. Ultrasound, MRCP, or ERCP findings must appear in the clinical record to establish medical necessity.

Pabau’s claims management software flags incomplete documentation fields before submission, reducing rework on K80.50 claims across gastroenterology and general surgery practices.

ICD-10 code K80.50: Quick reference details

ICD-10 code K80.50 sits in block K80-K87 (Disorders of gallbladder, biliary tract and pancreas) under category K80 (Cholelithiasis). The table below gives every field a coder or biller needs at a glance.

Per the Centers for Medicare and Medicaid Services ICD-10-CM code files, K80.50 carries no “code first” or “use additional code” mandatory instructional notes at the K80.50 level. If a secondary manifestation such as obstructive jaundice is documented and clinically significant, it may be assigned as an additional code per general ICD-10-CM sequencing guidelines.

What choledocholithiasis without obstruction means clinically

Choledocholithiasis is the presence of one or more calculi (stones) in the common bile duct (CBD) or hepatic bile ducts. ICD-10 code K80.50 applies specifically when imaging or endoscopy confirms a bile duct stone and the clinical record documents all three of the following: No acute cholangitis, no acute or chronic cholecystitis, and no current biliary obstruction.

The “without obstruction” qualifier is the one coders most often overlook. A stone can sit in the CBD for days or weeks without fully blocking bile flow. When it does block flow, bilirubin rises, the CBD dilates on ultrasound, and the patient may develop jaundice. At that point, the code is no longer K80.50.

• Imaging that confirms K80.50: Abdominal ultrasound showing a CBD stone without ductal dilation; MRCP (magnetic resonance cholangiopancreatography) identifying a stone without upstream biliary dilation; ERCP (endoscopic retrograde cholangiopancreatography) with stone retrieval when labs are normal or mildly abnormal.
• Lab pattern consistent with K80.50: Normal or mildly elevated total bilirubin, ALP, and GGT without the spike pattern that signals obstruction. Fever and leukocytosis are absent.
• What takes the case out of K80.50: CBD dilation greater than 8-10 mm on ultrasound, total bilirubin above 1.5-2 mg/dL with a rising trend, fever above 38°C, or Charcot’s triad (fever, jaundice, right upper quadrant pain). Any of these moves the case toward K80.51 or the cholangitis subcategories.

Attending physicians must state the absence of obstruction explicitly in the clinical note. “CBD stone, no obstruction” is acceptable documentation. “CBD stone” alone is not sufficient, because a coder cannot infer the absence of obstruction from a stone diagnosis without supporting language.

What K80.50 excludes: Inclusions, exclusions, and boundaries

The K80 category uses Excludes1 notes to prevent incorrect simultaneous coding. K80.50 is excluded when any of the following conditions are separately documented and coded.

K80.50 also has no laterality because the common bile duct is a single structure. Coders sometimes search for a “left” or “right” variant and find none – that is by design, not an omission. Verify codes against the CDC/NCHS ICD-10-CM web tool to confirm current-year descriptor accuracy before submission.

K80.50 vs K80.51: Without obstruction vs with obstruction

K80.50 and K80.51 are the most commonly confused code pair in the K80 family. The only difference is the obstruction qualifier, but that single character change carries significant clinical and billing implications.

The documentation cue that determines which code to assign is straightforward: If the operative or endoscopy note or the radiology report states “no biliary obstruction,” “CBD not dilated,” or “no upstream dilation,” K80.50 is correct. If the report mentions dilated CBD, obstructive pattern on labs, or clinical jaundice, the physician must be queried for clarification before the coder assigns K80.50 or upgrades to K80.51.

K80.50 vs neighbouring K80 subcodes: Full comparison

K80.50 is one of eight commonly billed K80 subcodes. Understanding the full family prevents miscoding when a patient has both a gallbladder stone and a bile duct stone, or when cholangitis complicates the presentation. A bile duct stone can also trigger acute pancreatitis. That episode codes to K85.1x once the physician links it to the stone, while K85.90 covers pancreatitis with no documented cause.

Use the AAPC ICD-10-CM code lookup to browse the full K80 family with instructional notes and crosswalk data. The WHO ICD-10 browser provides the international classification context for K80.50 when a practice treats patients under a global billing framework.

Procedure codes commonly paired with ICD-10 code K80.50

ICD-10 code K80.50 must support the medical necessity of every procedure on the same claim. The diagnosis alone does not guarantee coverage. The clinical record must demonstrate that the procedure was necessary given the confirmed bile duct stone and the documented absence of obstruction. When the endoscopist cuts the biliary sphincter to reach that stone, the incision is billed as 43262. If the same physician supervises and interprets the fluoroscopy of the bile ducts, that work is reported with 74328.

ERCP bundling rules under the 43260-43278 series change with CPT updates. Verify current unbundling edits before submitting multiple ERCP component codes on the same date of service. Pabau’s claims management software tracks paired diagnosis-to-procedure relationships and flags bundling mismatches before the claim reaches the clearinghouse.

Documentation requirements for K80.50 payer review

Payers reviewing K80.50 claims look for four categories of documentation. Missing any one of them is enough to generate a denial or a request for additional information.

• Imaging report: Ultrasound, MRCP, or ERCP report must name the bile duct stone and confirm it. “Possible cholelithiasis” or “suspected CBD stone” without imaging confirmation is insufficient for a definitive K80.50 code. The report must be in the chart before the claim is submitted.
• Lab values in context: Liver function tests (bilirubin, ALP, GGT, AST, ALT) must be present in the record. Normal or mildly abnormal values support K80.50. Markedly abnormal values without a physician note addressing the absence of obstruction will trigger a query or audit.
• Attending physician’s documented diagnosis: The clinical note must state the diagnosis using language the coder can map to K80.50. “CBD calculus without obstruction or infection” is ideal. “Biliary colic” alone is a symptom code and does not support K80.50 as the definitive diagnosis.
• Explicit absence of complications: The note must actively exclude cholangitis and obstruction. “Patient afebrile, no jaundice, CBD 5 mm in diameter” gives the coder the clinical picture needed. A note that simply lists the stone without addressing complications leaves the coder unable to distinguish K80.50 from K80.51 or K80.30.

Practices committed to medical billing compliance build documentation checklists for high-frequency biliary codes like K80.50 directly into their clinical workflows. Pabau’s Claim.MD clearinghouse integration validates the claim against payer edits in real time, catching missing diagnosis-to-procedure links before submission rather than after a denial arrives.

Common claim denial reasons for ICD-10 code K80.50 and how to prevent them

K80.50 denials cluster around four predictable failure points. Each has a corrective action that can be built into the pre-submission workflow.

Understanding denial management workflows for biliary codes prevents the rework cycle that costs gastroenterology practices hours per week. For the specific denial reason codes that payers attach to K80.50 rejections, see the denial codes in medical billing reference for CARC code interpretations and appeal language.

Prior authorization considerations for K80.50 procedures

Medicare generally does not require prior authorization for ERCP or laparoscopic cholecystectomy in the inpatient or outpatient hospital setting, though this is subject to change with CMS Prior Authorization model updates and should be verified against current CMS transmittals before assuming it applies to a specific claim. Commercial insurers vary significantly by plan.

• Medicare: Prior auth not routinely required for ERCP or cholecystectomy. Medical necessity documentation (imaging, labs, attending diagnosis) must still be in the chart.
• Commercial PPOs: Many require prior auth for outpatient ERCP. Some plans require auth for cholecystectomy only when performed electively. Verify by plan, not by insurer name.
• Medicare Advantage plans: These function under commercial plan rules even though they carry Medicare branding. Prior auth requirements are set by the plan sponsor and vary widely.
• Prior auth submission package for K80.50: Include the radiology or MRCP report identifying the CBD stone, the most recent LFT panel, the attending physician’s clinical note stating the diagnosis and absence of obstruction, and the CPT codes being requested. Incomplete auth packages are the second most common reason for auth denials on biliary procedures.

Specific payer prior authorization requirements change frequently. Never state that a specific payer requires or does not require auth based on historical practice alone. Always verify against the current payer policy document or provider portal before the procedure is scheduled.

K80.50 in practice: Clinical scenario examples

These four scenarios illustrate where K80.50 applies and where it does not. Each is a common presentation in gastroenterology and general surgery practices.

1. Incidental CBD stone on pre-op ultrasound, asymptomatic: Patient scheduled for elective cholecystectomy for cholelithiasis. Pre-op ultrasound identifies a 4 mm CBD stone incidentally. LFTs normal, CBD 6 mm diameter, no fever, no jaundice. Surgeon documents “CBD calculus, no obstruction.” Correct code: K80.50. The gallbladder stone (K80.20) is coded additionally if the gallbladder is also removed.
2. CBD stone with mildly elevated liver enzymes, no jaundice: Patient presents with right upper quadrant pain. MRCP shows a 7 mm CBD stone. Bilirubin 1.3 mg/dL (mildly elevated), ALP 180 U/L (mildly elevated), no fever, no jaundice, CBD diameter 7 mm. Gastroenterologist documents “choledocholithiasis without obstruction.” Correct code: K80.50. ERCP with stone removal is planned semi-electively.
3. CBD stone with fever and jaundice: Patient presents with Charcot’s triad (fever, jaundice, right upper quadrant pain). CBD dilated to 14 mm on ultrasound, bilirubin 4.2 mg/dL. Physician diagnoses acute cholangitis with choledocholithiasis. Correct code: K80.31 (with acute cholangitis, with obstruction) or K80.30 depending on obstruction documentation. K80.50 is incorrect here.
4. Gallbladder stone only, no CBD involvement: Patient has symptomatic cholelithiasis on ultrasound. CBD is 4 mm and normal. No CBD stone identified on MRCP or intraoperative cholangiography. Correct code: K80.20 (gallstone without cholecystitis, without obstruction). K80.50 is incorrect because there is no bile duct calculus.

How to streamline K80.50 coding and billing in your practice

Gastroenterology and general surgery practices that submit high volumes of K80.50 claims benefit from a structured pre-submission workflow. The documentation failures above are preventable when the right fields are captured at the point of care rather than retrieved retrospectively during a denial appeal.

• Template the documentation triggers: Build a biliary coding prompt into the clinical note template that asks: CBD diameter on imaging, presence or absence of jaundice, bilirubin and ALP result, and physician’s explicit obstruction statement. A note that answers all four fields gives the coder everything needed without a query.
• Track K80.50 vs K80.51 split rate: If your practice is submitting K80.51 (with obstruction) far more often than K80.50, or vice versa, review a sample of charts. The clinical population should show a mix. A heavily skewed split often means coders are defaulting to one code without checking the obstruction qualifier.
• Automate clearinghouse validation: Submitting through Pabau’s Claim.MD clearinghouse integration routes K80.50 claims through real-time eligibility checks and payer edit scrubbing before the claim reaches the payer. Claims flagged for missing documentation or diagnosis-procedure mismatches are returned to the billing team before they generate a denial, not after.
• Build a prior auth tracker for biliary procedures: Maintain a live record of which commercial plans in your payer mix require prior auth for ERCP and cholecystectomy. Update it quarterly. A missed auth is a denial that takes 30-60 days to appeal and often results in partial payment at best.

Understanding the fundamentals of medical billing at the diagnosis-code level, combined with revenue cycle management processes that catch errors upstream, is what separates practices that consistently collect on K80.50 claims from those that spend significant staff time on rework. For a plain-language overview of how clearinghouses fit into that process, Pabau’s guide to the clean claim submission process covers the validation steps a K80.50 claim must pass before the payer adjudicates it.

Automate your billing documentation before it becomes a denial

Pabau flags incomplete documentation fields and submits claims through Claim.MD for real-time payer validation. Gastroenterology and general surgery practices use it to reduce K80.50 rework and get paid faster.

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Conclusion

ICD-10 code K80.50 is a precise, billable code that requires the absence of three distinct complications – cholangitis, cholecystitis, and obstruction. Getting it right is less about memorising the descriptor and more about ensuring the clinical record actively documents what is not present, not just what is.

Pabau’s claims management software integrates with Claim.MD to validate K80.50 claims against payer edits in real time, reducing denials before they reach the payer. If your gastroenterology or general surgery practice is losing time to K80.50 rework, book a demo to see how Pabau handles the billing workflow from documentation to clearinghouse submission.

Continue your research

Need a clearinghouse that validates biliary claims before submission? Pabau’s Claim.MD clearinghouse integration scrubs K80.50 and paired procedure codes against payer edits in real time.

Unfamiliar with how denial codes map to K80.50 rejections? Denial codes in medical billing explains CARC codes and appeal language for biliary claim rejections.

Want to understand what makes a gastrointestinal claim clean? Clean claim submission walks through the validation steps a K80.50 claim must pass before payer adjudication.

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