The provider documented both mild cognitive impairment and unspecified degenerative disease of the nervous system on the same encounter. The Excludes1 note at code G31.84, Mild cognitive impairment, so stated, excludes code G31.9, Degenerative disease of the nervous system, unspecified. Based on the advice in Coding Clinic, Fourth Quarter 2018, pages 87-88, only the code referenced in the Excludes1 note is assigned, therefore, should code G31.9 be assigned, because it is the referenced code, even though a more specific condition, mild cognitive impairment is documented?
Assign code G31.84, Mild cognitive impairment, so stated, for documentation of mild cognitive impairment and degenerative disease of nervous system, unspecified. Per coding convention, codes titled “unspecified” are for use when the information in the medical record is insufficient to assign a more specific code. In this case, a more specific condition is documented; therefore, code G31.9 is not assigned.