Is K66 a billable ICD-10-CM code?

No. K66 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does K66 sit in the tabular list?

Diseases of the digestive system (K00-K95), in the block Diseases of peritoneum and retroperitoneum (K65-K68).

K66

K66 — Other disorders of peritoneum

Non-billable headerICD-10-CM

K66 is a non-billable header ICD-10-CM code for other disorders of peritoneum. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes2 — not included here, but may coexist

The excluded condition is not part of this code, but a patient can have both. You may code both.

ascites (R18.-)
peritoneal effusion (chronic) (R18.8)

Risk adjustment

K66 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Code to one of these instead K66

4 child codes. Green means billable.

Questions about K66

Is K66 a billable ICD-10-CM code?: No. K66 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does K66 sit in the tabular list?: Diseases of the digestive system (K00-K95), in the block Diseases of peritoneum and retroperitoneum (K65-K68).