Z42.1 ICD-10-CM Code: Encounter for breast reconstruction following mastectomy
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Inpatient Payment Groups (MS-DRG)
MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0 (FY2026), Appendix B.
- MS-DRG 606 — MINOR SKIN DISORDERS WITH MCC (MDC 09)
- MS-DRG 607 — MINOR SKIN DISORDERS WITHOUT MCC (MDC 09)
A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.
Code Set: Valid FY2026 and FY2027. FY2026 took effect October 1, 2025.
Official Registry Overview & Definition
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for Z42.1 in the official ICD-10-CM tabular list.
Excludes1 — Not Coded Here
Conditions that can never be reported with this code; the two are mutually exclusive.
- deformity and disproportion of reconstructed breast (N65.1-)
- encounter for cosmetic plastic surgery (Z41.1)
- encounter for plastic surgery for treatment of current injury - code to relevent injury
Excludes2 — Not Included Here
Conditions not covered by this code, but which may be reported alongside it when both are present.
- follow-up examination for medical surveillance after treatment (Z08-Z09)
Nearest Codes in This Family
Official ICD-10-CM classifications closest to Z42.1 in its code family, with their registry titles.
Indexed Clinical Terms (2)
Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.
- Admission (for), breast reconstruction following mastectomy
- Encounter (with health service) (for), breast reconstruction following mastectomy