K66

Other disorders of peritoneum

FY2027Chapter 11: Diseases of the digestive system/K65–K6A Diseases of peritoneum, retroperitoneum and pelvis

Non-billable headerNot valid on its own. Use one of the more specific codes under it.

K66 is a non-billable ICD-10-CM code category for other disorders of peritoneum. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are K66.0 Peritoneal adhesions (postprocedural) (postinfection); K66.1 Hemoperitoneum; K66.8 Other specified disorders of peritoneum and K66.9 Disorder of peritoneum, unspecified. Its coding notes include 10 Excludes2 entries.

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

This code
  • ascites (R18.-)
  • peritoneal effusion (chronic) (R18.8)
Also from chapter/block level (8 notes)
Inherited from Chapter 11 Diseases of the digestive system
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

More specific codes under K66 4