Alzheimer's Disease ICD-10-CM codes

Category G30 has four codes: G30.0 (early onset, generally before age 65), G30.1 (late onset), G30.8 (other Alzheimer's disease), and G30.9 (unspecified). G30.9 is the default when onset is not documented. Age at the time of the encounter does not determine onset; the provider must state early or late onset.

Alzheimer's disease is almost always coded as a pair. The G30 code is sequenced first, followed by a dementia code from F02.- (dementia in other diseases classified elsewhere) that reports severity and disturbance: F02.80 for unspecified severity without disturbance, F02.A0 mild, F02.B0 moderate, F02.C0 severe, and the .11, .18, .2, .3, and .4 endings for agitation, other behavioral, psychotic, mood, and anxiety disturbance. The tabular instruction at G30 says to use an additional code to identify the dementia.

If the provider documents Alzheimer's disease without describing dementia, do not assume F02.80. The G30 note also allows F06.7- (mild neurocognitive disorder due to known physiological condition) for early disease without dementia, so query when the cognitive status is unclear. Never use F03.- (unspecified dementia) with Alzheimer's disease; G30 carries an Excludes1 note against senile dementia NOS (F03.-). Add Z91.83 for documented wandering, and report delirium (F05) or depression as additional codes.