S32.401B
Unspecified fracture of right acetabulum, initial encounter for open fracture
S32.401B (also written S32401B) is a billable ICD-10-CM diagnosis code for unspecified fracture of right acetabulum, initial encounter for open fracture. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 846 codes in category S32 (Fracture of lumbar spine and pelvis). Its 7th character, B, means initial encounter for open fracture. Its coding notes include a Code first instruction, a Use additional code instruction, a Code also instruction, 1 Excludes1 entry and 9 Excludes2 entries.
7th character
Category S32 requires a 7th character.
Guidelines tips
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
A fracture not stated as open or closed is coded closed, and one not stated as displaced or not displaced is coded displaced. Nonunion and malunion have their own 7th characters.
The 7th character depends on whether the patient is in active treatment, not on who sees the patient. An aftercare Z code is not used for injury aftercare.
Each injury gets its own code unless a combination code exists, with the most serious injury first. Superficial injuries at the same site as a more severe injury are not coded. Injuries during medical care are coded as complications.
Code first
If the underlying condition listed here is present and known, sequence it first.
Use additional code
Add the listed code as a secondary code, if known.
Also from chapter/block level (1 note)
- code to identify any retained foreign body, if applicable (Z18.-)
Code also
Two codes may be needed to describe the condition. This note gives no sequencing order.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (8 notes)
- birth trauma (P10-P15)
- obstetric trauma (O70-O71)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the Musculoskeletal Rehabilitation clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026IRF 60% Rule
On the CMS list of diagnoses used to determine presumptive compliance with the IRF 60 percent rule.
Source: CMS IRF Presumptive Compliance-3, FY 2027 IRF PPS final rule files, effective for discharges on or after October 1, 2026Hospital MCC
Counts as a major complication or comorbidity (MCC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 253 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.
Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix CHAC
On the CMS list of hospital-acquired conditions (HAC 05: Falls and Trauma). When the claim reports it with a present-on-admission (POA) indicator of N (not present) or U (documentation insufficient), CMS does not pay the CC or MCC DRG for it. A POA of Y (present) or W (clinically undetermined) is paid normally.
Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix I; CMS Hospital-Acquired Conditions (HAC) Coding page, POA indicator payment tableIncludes
Further defines or gives examples of the content of the category.
- fracture of lumbosacral neural arch
- fracture of lumbosacral spinous process
- fracture of lumbosacral transverse process
- fracture of lumbosacral vertebra
- fracture of lumbosacral vertebral arch
Also from chapter/block level (6 notes)
- injuries to the abdominal wall
- injuries to the anus
- injuries to the buttock
- injuries to the external genitalia
- injuries to the flank
- injuries to the groin
Notes
- A fracture not indicated as displaced or nondisplaced should be coded to displaced
- A fracture not indicated as opened or closed should be coded to closed
Also from chapter/block level (2 notes)
- Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
- The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.