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CMS SOM App. A, Tag A-0286

Patient Safety, Medical Errors & Adverse Events

activein force · 2026-07-22 – presentas-observed

§§482.21(a)(1), 482.21(a)(2), 482.21(c)(2), & 482.21(e)(3)

§482.21(a) Standard: Program Scope.

• The program must include, but not be limited to, an ongoing program that shows

measurable improvement in indicators for which there is evidence that it will… identify and

reduce medical errors.

• The hospital must measure, analyze, and track…adverse patient events….

§482.21(c) Standard: Program Activities.

(2) Performance improvement activities must track medical errors and adverse patient

events, analyze their causes, and implement preventive actions and mechanisms that

include feedback and learning throughout the hospital.

§482.21(e) Standard: Executive Responsibilities. The hospital’s governing body (or organized

group or individual who assumes full legal authority and responsibility for operations of the

hospital), medical staff, and administrative officials are responsible and accountable for

ensuring the following: …

(3) That clear expectations for safety are established.

Interpretive Guidance §§482.21(a)(1), 482.21(a)(2), 482.21(c)(2), & 482.21(e)(3)

Medical errors and adverse events

The reporting mechanism for medical errors and adverse events is at the discretion of the hospital.

CMS does not specify the type of reporting mechanism to be used, but expects that the system will permit

the hospital to track and analyze medical errors and adverse events in an effective and meaningful

manner. As appropriate, hospitals should educate all hospital staff and contract staff on what is

considered a medical error and an adverse event, as well as when and how to report these events.

CMS has adopted the following definition of an error from the Quality Interagency Coordination Task

Force (QuIC) (68 FR 3435, 3436, January 24, 2003):

“An error is defined as the failure of a planned action to be completed as intended or the use of a wrong

plan to achieve an aim. Errors can include problems in practice, products, procedures, and systems.”

There are many types of medical errors, including, but not limited to:

• Medication administration errors - wrong medication, wrong dosage, wrong patient, etc.;

• Surgical errors - wrong patient, wrong site, retained instrument, etc.;

• Equipment failure – defibrillator without working batteries, IV pump that results in inadvertent

dosing, alarms not working properly, etc.;

• Infection control errors – poor aseptic technique, incorrect processing of sterile instruments and

equipment, incorrect isolation practices, lack of standard precautions, etc.;

• Blood transfusion-related errors – wrong patient, wrong blood product administered, etc.; and

• Diagnostic errors – misdiagnoses leading to incorrect choice of therapy, failure to use an indicated

diagnostic test, misinterpretation of test results, failure to act properly on abnormal results.

Not every medical error results in harm to a patient; the error may be detected and addressed before a

harmful effect can occur (a “near miss”) or the consequence of the error may be minimal. From a

patient safety perspective, a near miss is considered an error and much can be learned from the near

miss in terms of system weaknesses that could, in the future, result in actual harm to patients.

Therefore, hospitals must track and analyze errors that result in near misses, and focus on their

prevention and reduction.

While the regulation also specifically calls for measuring, analyzing, and tracking of adverse events,

adverse events may or may not be preventable. A preventable adverse event is an injury caused by an

error. Section 482.70 defines an adverse event as “an untoward, undesirable, and usually unanticipated

event that causes death or serious injury, or the risk thereof.”

Analysis of Causes of Medical Errors and Adverse Events

Hospitals should analyze medical errors and adverse events to determine the cause(s) by using a

systemic approach for determining the cause of the error and for implementing appropriate preventive

actions.

Implementing Improvement/Preventive Strategies

After the systemic analysis of the error or adverse event has led to the identification of the cause of the

event, hospitals should develop and implement preventive actions to improve the quality and safety

associated with the event or the error. Preventive actions include, but are not limited to, changes in

policies and procedures, repairing or replacing equipment, staff education and training, etc. Where

appropriate, the hospital should make all affected staff aware of the strategies and related actions it has

implemented to correct and prevent specific errors and adverse events, and also provide applicable

training. Hospitals should be able to provide evidence of the implemented changes, such as documented

staff education and training, documentation of new or revised policies, evidence that equipment has

been repaired or replaced, etc.

Evaluating Changes and Sustaining Improvement

The hospital should also have a method to assess whether the strategies and actions it has implemented

resulted in improved outcomes and that those improved outcomes are sustained over time. This means

the hospital should collect data that enables the hospital to determine whether indicators, related to a

specific area targeted for change, actually demonstrated an improvement after implementation of the

changes.

For example, the hospital should continue to periodically collect data on proper hand hygiene and then

analyze the data to determine if the solution has resulted in sustained improvement in handwashing

compliance. If the analysis of the periodic collection of handwashing data shows that the solution has

not resulted in a sustained improvement over an appropriate period of time, a new or revised

strategy/solution must be implemented, with subsequent data collection and monitoring to evaluate the

effectiveness of the new solution.

Prospective hospitals applying for initial certification in Medicare

A facility seeking Medicare program initial certification as a hospital may not have been in operation

long enough to demonstrate extensive internal data collection for the identification of opportunities for

improvement based on the monitoring data. However, it must be able to show that it has an active data

collection and analysis infrastructure in place, and indicate when it expects to have sufficient data to

begin analysis. In addition, because hospitals may utilize quality indicators from outside sources to

prioritize QAPI program activities, an initial applicant would still be expected to provide evidence of

implementing improvement actions based on selected indicators from outside sources.

Survey Procedures

• Ask to see evidence of the medical error/adverse event reporting system. Ask for a copy of

the medical error and adverse event reporting policy. Ask for a demonstration of how to use

the system and how the system is able to organize the reported data for meaningful analysis.

 Can the system organize the data by type of error/adverse event?

 Can the system organize the data by dates to show trends over time?

 Can the system organize the data by shift, by unit where the error occurred, etc.?

• Ask to see evidence of hospital-wide staff education and training regarding what errors and

adverse events must be reported and how to report them. Look at the materials used for

education and training.

 Are there training records to show staff received the training?

• Interview staff in various units to assess their understanding of identifying and reporting

medical errors and adverse events.

• Select a sample of several (at least three) adverse events or errors the hospital has tracked

and ask to see written evidence it has used a systemic approach (e.g., root cause analysis

(RCA)) to analyze the cause of the events and errors), implemented changes based on the

identified causes to prevent further events or errors, conducted periodic data collection to

verify if the changes resulted in improvements, and analyzed the post-implementation data to

assess whether the improvement (if there was an improvement) was sustained over time.

History

Rev. 238; Issued: 03-20-26; Effective: 09-05-25; Implantation: 09-05-25

Provenance

Source
cms.gov
Retrieved
2026-07-22
Edition
som-2026-07-22
Content hash
aeafada439716234654fa2cd248bbb949cda039e4f32b506a99a05b1376635f9
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