The ICD-10-CM Diagnosis Code R4182 is a critical tool in medical coding, specifically used to classify Altered mental status, unspecified. This code is billable and specific, meaning it can be used for reimbursement purposes and provides a detailed level of diagnostic information. Valid from October 1, 2024, for the 2025 ICD-10-CM edition, R41.82 is the American modification of the international ICD-10 R41.82, with potential variations in other international versions.
What Does “Altered Mental Status” Mean?
Altered mental status (AMS) is a broad term in medicine describing a change in a person’s normal awareness and responsiveness to their environment. This can manifest in various ways, from confusion and disorientation to lethargy and even coma. It is crucial to understand that diagnosis code R4182 is applied when the altered mental status is unspecified. This means it is used when a more precise diagnosis is not yet determined or when the altered mental status is the primary focus of care, and the underlying cause is still under investigation.
Specificity and Application of R41.82
Diagnosis code R4182 is categorized under Chapter V of the ICD-10-CM, “Mental, Behavioral and Neurodevelopmental disorders” and more specifically under “Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified,” within the range R00-R99. The code is applicable when documenting a “change in mental status NOS” (Not Otherwise Specified). This “Applies To” note clarifies the situations where R41.82 is the appropriate code.
However, it’s equally important to understand when diagnosis code R4182 should not be used. The ICD-10-CM guidelines provide “Type 1 Excludes” notes, which are critical for accurate coding.
Type 1 Excludes for R41.82
A “Type 1 Excludes” note signifies that the excluded code should never be used concurrently with R41.82. This is because the two conditions are mutually exclusive. For diagnosis code R4182, Type 1 Excludes include:
- Altered level of consciousness (R40.-): If the altered mental status is specifically documented as an altered level of consciousness, such as stupor or coma, then codes within R40.- are more appropriate.
- Altered mental status due to known condition: Crucially, if the altered mental status is due to a known underlying condition, then the coding should focus on that condition. R41.82 is for when the cause is unspecified.
- Delirium NOS (R41.0): While delirium is a form of altered mental status, if “delirium” is specifically documented without further specification (NOS – Not Otherwise Specified), then diagnosis code R41.0 should be used instead.
Related and Adjacent ICD-10-CM Codes
Understanding the codes surrounding R41.82 provides further context. Diagnosis code R41.0, as mentioned, covers “Disorientation, unspecified,” which is a specific type of altered mental status. Other related codes in the vicinity include:
- R40.3 Persistent vegetative state and R40.4 Transient alteration of awareness: These address specific levels and durations of altered consciousness.
- R41 Other symptoms and signs involving cognitive functions and awareness: This broader category encompasses R41.82 and other cognitive and awareness-related symptoms.
- Codes from R41.81 Age-related cognitive decline to R41.89 Other symptoms and signs involving cognitive functions and awareness: These codes detail various specific cognitive deficits, highlighting that R41.82 is for when the altered mental status is not specified further.
Historical Context of Diagnosis Code R4182
Diagnosis code R4182 is a relatively recent addition to the ICD-10-CM, becoming a new code in 2016 (effective October 1, 2015). There have been no changes to the code definition or application from 2016 through the 2025 edition. This stability indicates its established role in medical coding for unspecified altered mental status.
In Summary
Diagnosis code R4182, Altered mental status, unspecified, is a vital code for medical professionals and coders. It accurately represents cases where a patient presents with altered mental status, and the underlying cause is not yet determined or specified. Correct utilization of R41.82, understanding its exclusions, and recognizing its place within the broader ICD-10-CM coding system are essential for accurate medical documentation and appropriate reimbursement.
