ICD-10-CM Code Z42.1

Encounter for breast reconstruction following mastectomy

Version 2020 Billable Code Adult Diagnoses POA Exempt

Valid for Submission

Z42.1 is a billable code used to specify a medical diagnosis of encounter for breast reconstruction following mastectomy. The code is valid for the year 2020 for the submission of HIPAA-covered transactions. The code is exempt from present on admission (POA) reporting for inpatient admissions to general acute care hospitals.

The code Z42.1 is applicable to adult patients aged 15 through 124 years inclusive. It is clinically and virtually impossible to use this code on a patient outside the stated age range.

ICD-10:Z42.1
Short Description:Encounter for breast reconstruction following mastectomy
Long Description:Encounter for breast reconstruction following mastectomy

Tabular List of Diseases and Injuries

The Tabular List of Diseases and Injuries is a list of ICD-10 codes, organized "head to toe" into chapters and sections with guidance for inclusions, exclusions, descriptions and more. The following references are applicable to the code Z42.1:

Type 1 Excludes

Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
  • deformity and disproportion of reconstructed breast N65.1

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code Z42.1 are found in the index:


Code Edits

The Medicare Code Editor (MCE) detects and reports errors in the coding of claims data. The following ICD-10 Code Edits are applicable to this code:

  • Adult diagnoses - Adult. Age range is 15–124 years inclusive (e.g., senile delirium, mature cataract).

Diagnostic Related Groups

The ICD-10 code Z42.1 is grouped in the following groups for version MS-DRG V37.0 What are Diagnostic Related Groups?
The Diagnostic Related Groups (DRGs) are a patient classification scheme which provides a means of relating the type of patients a hospital treats. The DRGs divides all possible principal diagnoses into mutually exclusive principal diagnosis areas referred to as Major Diagnostic Categories (MDC).
applicable from 10/01/2019 through 09/30/2020.

  • 606 - MINOR SKIN DISORDERS WITH MCC
  • 607 - MINOR SKIN DISORDERS WITHOUT MCC

Present on Admission (POA)

Z42.1 is exempt from POA reporting - The Present on Admission (POA) indicator is used for diagnosis codes included in claims involving inpatient admissions to general acute care hospitals. POA indicators must be reported to CMS on each claim to facilitate the grouping of diagnoses codes into the proper Diagnostic Related Groups (DRG). CMS publishes a listing of specific diagnosis codes that are exempt from the POA reporting requirement. Review other POA exempt codes here .

CMS POA Indicator Options and Definitions
POA Indicator CodePOA Reason for CodeCMS will pay the CC/MCC DRG?
YDiagnosis was present at time of inpatient admission.YES
NDiagnosis was not present at time of inpatient admission.NO
UDocumentation insufficient to determine if the condition was present at the time of inpatient admission.NO
WClinically undetermined - unable to clinically determine whether the condition was present at the time of inpatient admission.YES
1Unreported/Not used - Exempt from POA reporting. NO

Convert Z42.1 to ICD-9

  • V51.0 - Brst reconst fol mastect

Code Classification

  • Factors influencing health status and contact with health services (Z00–Z99)
    • Encounters for other specific health care (Z40-Z53)
      • Encntr for plast/recnst surg fol med proc or healed injury (Z42)

Code History

  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016
    (First year ICD-10-CM implemented into the HIPAA code set)
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020

Information for Patients


Breast Reconstruction

If you need a mastectomy, you have a choice about whether or not to have surgery to rebuild the shape of the breast. Instead of breast reconstruction, you could choose to wear a breast form that replaces the breast, wear padding inside your bra, or do nothing. All of these options have pros and cons. What is right for one woman may not be right for another.

Breast reconstruction may be done at the same time as the mastectomy, or it may be done later on. If radiation therapy is part of the treatment plan, your doctor may suggest waiting until after radiation therapy.

If you're thinking about breast reconstruction, talk to a plastic surgeon before the mastectomy, even if you plan to have your reconstruction later on.

A surgeon can reconstruct the breast in many ways. Some women choose to have breast implants, which are filled with saline or silicone gel. Another method uses tissue taken from another part of your body. The plastic surgeon can take skin, muscle, and fat from your lower abdomen, back, or buttocks.

The type of reconstruction that is best for you depends on your age, body type, and the type of cancer surgery that you had. A plastic surgeon can help you decide.

NIH: National Cancer Institute


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