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ICD-10-CM 2027 diagnosis code

K66.1Hemoperitoneum

✓ Billable / specificMCC — major complication/comorbidity

K66.1 is a valid, billable ICD-10-CM code for hemoperitoneum. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Hemoperitoneum.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About K66.1

K66.1 is the ICD-10-CM diagnosis code for Hemoperitoneum. It belongs to category K66 (other disorders of peritoneum), block K65-K6A (diseases of peritoneum, retroperitoneum and pelvis) and chapter 11 (diseases of the digestive system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within K66 (other disorders of peritoneum), K66.1 is specifically for Hemoperitoneum. Related codes cover peritoneal adhesions (postprocedural) (postinfection) (K66.0), other specified disorders of peritoneum (K66.8) and disorder of peritoneum, unspecified (K66.9).

Don't report K66.1 together with the conditions in its Excludes1 note: traumatic hemoperitoneum (S36.8-).

The conditions in its Excludes2 note aren't part of K66.1, but may be coded alongside it if the patient has both: retroperitoneal hematoma (K68.3) and retroperitoneal hemorrhage (K68.3).

As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 393 (Other Digestive System Diagnoses with MCC, relative weight 1.5881), DRG 394 (Other Digestive System Diagnoses with CC, relative weight 0.9228), DRG 395 (Other Digestive System Diagnoses without CC/MCC, relative weight 0.6382), DRG 791 (Prematurity with Major Problems, relative weight 4.1075) and DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), in MDC 06 (Diseases and Disorders of the Digestive System) and MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 568.81 (Hemoperitoneum (nontraumatic)).

Coding notes

Applicable toConditions and synonyms classified to this code
  • Peritoneal hematoma
  • Peritoneal hemorrhage
Excludes1Not coded here — never report together with this code
  • traumatic hemoperitoneum (S36.8-)
Excludes2Not included here — may be reported together if both conditions exist
  • retroperitoneal hematoma (K68.3)
  • retroperitoneal hemorrhage (K68.3)

Notes that apply from higher levels

Instructions written at a parent level also apply to K66.1.

› From K66 Other disorders of peritoneum
Excludes2
  • ascites (R18.-)
  • peritoneal effusion (chronic) (R18.8)

Broader instructions also apply from Chapter 11: Diseases of the digestive system.

Alphabetic index entries

7 entries

Terms in the official ICD-10-CM index that lead to K66.1.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period

MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period

ICD-9-CM equivalent

Converter →
  • 568.81Hemoperitoneum (nontraumatic)exact

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about K66.1

Is K66.1 billable?

Yes. K66.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can K66.1 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict K66.1 as a principal diagnosis.

Is K66.1 a CC or MCC?

K66.1 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does K66.1 group to?

K66.1 is used in the MS-DRG v44.0 logic for MS-DRG 393 (Other Digestive System Diagnoses with MCC), MS-DRG 394 (Other Digestive System Diagnoses with CC), MS-DRG 395 (Other Digestive System Diagnoses without CC/MCC), MS-DRG 791 (Prematurity with Major Problems) and MS-DRG 793 (Full Term Neonate with Major Problems). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for K66.1?

The CMS General Equivalence Mappings map K66.1 to ICD-9-CM 568.81.