K35.31 — Acute appendicitis with localized peritonitis and gangrene, without perforation
ICD-10-CM
Prior Authorization
No Prior Auth Required
Code is covered without prior authorization (high confidence)
Documentation Required
- Medical records must document that the ultrasound was limited to retroperitoneal structures when billing CPT 76770/76775/76776, including images/findings demonstrating limitation to the retroperitoneum.
- If the exam was expanded to include organs outside the retroperitoneum, documentation must reflect the expansion and support billing a full or limited abdominal ultrasound (CPT 76700/76705/76706).
- Claims and documentation should follow the complementary Local Coverage Determination L34577 and any applicable LCD requirements.
- This billing and coding article provides guidelines that complement Local Coverage Determination L34415 for CT of the abdomen and pelvis; consult LCD L34415 for specific coverage indications, limitations, and documentation requirements.
Key Coverage Criteria
- Retroperitoneal ultrasound (CPT 76770, 76775, 76776) is covered when the exam is limited solely to retroperitoneal structures.
- A full (complete) or limited abdominal ultrasound (CPT 76700, 76705, 76706) is covered when the exam includes organs or structures outside the retroperitoneum or when primary findings involve non-retroperitoneal structures (e.g., gallbladder, liver, spleen, common bile duct).
- CT abdomen is medically necessary to evaluate abdominal pain.
- CT abdomen is medically necessary to evaluate known or suspected abdominal masses or fluid collections.
- CT abdomen is medically necessary for evaluation of primary or metastatic malignancies in the abdomen.
- CT abdomen is medically necessary to evaluate abdominal inflammatory processes.
4 Active Policies
A55336 — Billing and Coding: Retroperitoneal Ultrasound
A56421 — Billing and Coding: CT of the Abdomen and Pelvis
L34577 — Retroperitoneal Ultrasound
L34415 — CT of the Abdomen and Pelvis
Related Codes
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