G31.84 ICD-10-CM Code: Mild cognitive impairment of uncertain or unknown etiology

G31.84 is the ICD-10-CM diagnosis code for mild cognitive impairment of uncertain or unknown etiology. Mild cognitive impairment with no clear identified cause; a condition where thinking and memory problems are noticeable but not severe enough to interfere significantly with daily life. G31.84 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering other degenerative diseases of the nervous system (g30-g32).

G31.84 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

This code is used when cognitive decline is documented but the underlying cause is uncertain or unknown.