Z42.1 — Encounter for breast reconstruction following mastectomy
Is Z42.1 billable?
Yes — Z42.1 is billable for FY2027. Z42.1 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. Z42.1 may be submitted for encounters from October 1, 2026 through September 30, 2027.
Z42.1 at a glance
| Code | Z42.1 |
|---|---|
| Description | Encounter for breast reconstruction following mastectomy |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does Z42.1 group to?
Z42.1 sits in MDC 09 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 606Minor Skin Disorders with MCCmedical
- 607Minor Skin Disorders without MCCmedical
How is Z42.1 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to Z42.1. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Admission › breast reconstruction following mastectomy (for)
- Encounter › breast reconstruction following mastectomy (with health service) (for)
Excludes1 — never code together
The conditions below can never be reported together with Z42.1 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- deformity and disproportion of reconstructed breast (N65.1-)
Excludes1 — never code together — inherited from Z42
The conditions below can never be reported together with Z42.1 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- encounter for cosmetic plastic surgery (Z41.1)
- encounter for plastic surgery for treatment of current injury - code to relevent injury
Excludes2 — not included here — inherited from Z40-Z53
The conditions below are not part of Z42.1, but a patient may have both at the same time. When documentation supports it, Z42.1 and the excluded code may both be reported.
- follow-up examination for medical surveillance after treatment (Z08-Z09)
How long has Z42.1 existed?
Z42.1 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.
Which codes are confused with Z42.1?
ICD-10-CM declares these codes mutually exclusive with Z42.1 — exactly one of each pair can be correct for a given encounter.