K56.3
BillableGallstone ileus
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is K56.3 an HCC code?
Yes. K56.3 maps to Intestinal Obstruction/Perforation under the CMS-HCC V28 risk adjustment model (and Intestinal Obstruction/Perforation under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for K56.3
For K56.3to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed K56.3 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
K56.3 is the ICD-10-CM diagnosis code for gallstone ileus. A blockage of the intestine caused by a gallstone that has eroded through the gallbladder wall into the intestine. This is a rare cause of intestinal obstruction. K56.3 sits in the ICD-10-CM chapter for diseases of the digestive system (k00-k95), within the section covering other diseases of intestines (k55-k64).
Under the CMS-HCC V28 risk adjustment model, K56.3 maps to Intestinal Obstruction/Perforation (HCC 78) with a community, non-dual, aged base RAF weight of 0.000. Under the older V24 model, K56.3 mapped to the same category but with a base RAF weight of 0.226 — V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Gallstone ileus requires documentation of both the gallstone and the intestinal obstruction for complete coding. Because K56.3 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for K56.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Gallstone ileus requires documentation of both the gallstone and the intestinal obstruction for complete coding
- •This condition typically occurs in elderly patients with a history of cholelithiasis; verify clinical context
Clinical Significance
K56.3 represents gallstone ileus, a rare cause of mechanical bowel obstruction occurring when a gallstone erodes through the gallbladder wall and impacts in the intestine. This condition typically affects elderly patients and represents a complex pathophysiology requiring both recognition of the obstructing stone and management of the underlying biliary pathology.
Documentation Requirements
- ✓Imaging demonstrating intestinal obstruction with impacted gallstone
- ✓Evidence of gallstone in intestinal lumen causing blockage
- ✓Documentation of Rigler's triad (pneumobilia, obstruction, ectopic stone) when present
- ✓Assessment of gallbladder pathology and fistulous communication
- ✓Surgical intervention to remove obstructing stone
- ✓Evaluation for concurrent biliary complications
- ✓Documentation of complete vs partial obstruction
- ✓Post-operative management and complications
Commonly Confused Codes
- •K80.20 — Calculus of gallbladder without obstruction (primary biliary disease rather than intestinal obstruction)
- •K56.49 — Other impaction of intestine (non-gallstone impaction)
- •K56.60 — Partial intestinal obstruction unspecified (when gallstone cause not documented)
- •K87 — Disorders of gallbladder following cholecystectomy (post-surgical rather than gallstone ileus)
- •K56.69 — Other intestinal obstruction (when gallstone mechanism not specified)