Alzheimer's disease is a progressive disorder causing degeneration of brain cells and eventual death in those suffering from it. Your ability to accurately code for Alzheimer’s disease is essential because Alzheimer’s is frequently diagnosed in home health and is a primary reason for admission.
To correctly code for Alzheimer’s disease, you must first understand that the term “dementia” is a general term which describes a continuous decline in thinking, behavioral and social skills and disrupts a person’s ability to function independently.
Alzheimer’s disease is the most common form of dementia, affecting 60 to 80% of all dementia cases, and is the sixth leading cause of death in the U.S.
Four codes for the disease
Find Alzheimer’s disease codes in Chapter 6 (Diseases of the Nervous system), in the section “Other degenerative diseases of the nervous system.”
All Alzheimer’s disease codes are valid primary diagnosis codes under the Patient-Driven Groupings Model (PDGM), although no comorbidity points are assigned. When coded as a primary diagnosis, remember to include interventions addressing Alzheimer’s disease and any manifestations in the plan of care.
Assign one of four codes to Alzheimer’s disease. To code, first begin in the Alphabetic Index with terms “Disease, Alzheimer’s” and note that the default code is G30.9 (Alzheimer’s disease, unspecified).
The italicized brackets next to the code in the Alphabetic Index indicate that it is part of an etiology/manifestation combination, so you need two codes to correctly code each type of Alzheimer’s disease.
Second codes for the presence, or the lack of, behaviors
The second code refers to the absence or presence of any behavioral disturbance that the patient exhibits, and further serves to describe the patient’s status. Codes F02.80 (Dementia in other diseases classified elsewhere without behavioral disturbance) and F02.81 (Dementia in other diseases classified elsewhere with behavioral disturbance) capture these patient statuses.
Find the manifestation codes for Dementia in diseases classified elsewhere in Chapter 5, (Mental, Behavioral, and Neurodevelopmental Disorders) under the category “Dementia in other diseases classified elsewhere.” Here are four coding rules to remember:
- The etiology/manifestation coding convention states that you must always associate manifestation codes with, and code them immediately after, the etiology code.
- Your providers may or may not state whether a patient with Alzheimer’s disease exhibits behaviors, so if not stated, use the default F02.80.
- Your provider documentation should state that a patient exhibits a general or specific behavior described above in order to code F02.81.
- An Excludes 1 note in the tabular index instructs that when you code Alzheimer’s you cannot also code senile brain degeneration or the more general terms, senile dementia or senility.
Dementia patients sometimes exhibit behavioral disturbances, including those described as aggressive or violent, and also include wandering, which has its own code — Z91.83 (Wandering in diseases classified elsewhere). Find this code in Chapter 21 (Factors Influencing Health Status and Contact with Health Services).
Code for delirium, or sundowning
Alzheimer’s patients may also experience another disruptive condition, delirium, not classified as a behavioral disturbance.
Patients with delirium show characteristics of inattention, disorganized thinking and altered levels of consciousness. This delirium is called sundowning if this happens later on in the day or evening. Delirium in an Alzheimer’s patient is considered a manifestation — code it as F05 (Delirium due to known physiological condition) and not as delirium NOS which falls under a symptom code R41.0 (Disorientation, unspecified) found in Chapter 18.
Distinguish between early and late onset
About 5% of Alzheimer’s patients develop symptoms before age 65 and are “patients with early-onset Alzheimer’s disease” (EOAD), the second code under the listing for Alzheimer’s in the Alphabetical Index, G30.0 (Alzheimer's disease with early onset).
The overwhelming majority of Alzheimer’s patients have the late-onset form of the disease and are diagnosed after age 65. The code for late onset Alzheimer’s disease is G30.1 (Alzheimer's disease with late onset).
Alzheimer’s disease that has a specific inherited genetic link is “familial Alzheimer’s disease” and you code it as G30.8 (Other Alzheimer’s disease). Ongoing research associates traumatic or cumulative brain injuries throughout life to the development of Alzheimer’s, and when a physician states as such, code that to G30.8 also.
Remember: Your provider must specify the diagnosis of early or late onset Alzheimer’s disease for you to use those codes. If your provider does not state early or late onset, use the default code G30.9.