2025 ICD-10-CM Diagnosis Code Y66

Nonadministration of surgical and medical care

ICD-10-CM Code:
Y66
ICD-10 Code for:
Nonadministration of surgical and medical care
Is Billable?
Yes - Valid for Submission
Code Navigator:

Y66 is a billable diagnosis code used to specify a medical diagnosis of nonadministration of surgical and medical care. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2024 through September 30, 2025.

Code Classification

  • External causes of morbidity and mortality
    V01–Y99
    • Complications of medical and surgical care
      Y62-Y84
      • Nonadministration of surgical and medical care
        Y66

Clinical Classification

Clinical Classifications group individual ICD-10-CM diagnosis codes into broader, clinically meaningful categories. These categories help simplify complex data by organizing related conditions under common clinical themes.

They are especially useful for data analysis, reporting, and clinical decision-making. Even when diagnosis codes differ, similar conditions can be grouped together based on their clinical relevance. Each category is assigned a unique CCSR code that represents a specific clinical concept, often tied to a body system or medical specialty.

External cause codes: complications of medical and surgical care, initial encounter

CCSR Code: EXT025

Inpatient Default: X - Not applicable.

Outpatient Default: X - Not applicable.

Index of External Cause of Injuries

References found for this diagnosis code in the External Cause of Injuries Index:

    • Nonadministration(of)
      • surgical and medical care
    • Premature cessation(of) surgical and medical care

Convert Y66 to ICD-9-CM

Below are the ICD-9 codes that most closely match this ICD-10 code, based on the General Equivalence Mappings (GEMs). This ICD-10 to ICD-9 crosswalk tool is helpful for coders who need to reference legacy diagnosis codes for audits, historical claims, or approximate code comparisons.

Medical misadventure NEC

ICD-9-CM: E876.8

Approximate Flag - The approximate mapping means this ICD-10 code does not have an exact ICD-9 equivalent. The matched code is the closest available option, but it may not fully capture the original diagnosis or clinical intent.

Patient Education


Patient Safety

You can help prevent medical errors by being an active member of your health care team. Research shows that patients who are more involved with their care tend to get better results. To reduce the risk of medical errors, you can:

  • Ask questions if you have doubts or concerns. Take a relative or friend to your doctor appointment to help you ask questions and understand answers.
  • Make sure you understand what will happen if you need surgery
  • Tell your health care providers about all the medicines you take, including over-the-counter drugs and dietary supplements. Tell them if you have any allergies or bad reactions to anesthesia. Make sure you know how to take your medications correctly.
  • Get a second opinion about treatment options
  • Keep a copy of your own medical history

Agency for Healthcare Research and Quality


[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.