R94.09Abnormal results of other function studies of central nervous system

R94.09 is the ICD-10-CM diagnosis code for abnormal results of other function studies of central nervous system. It belongs to category R94 (abnormal results of function studies), block R90-R94 (abnormal findings on diagnostic imaging and in function studies, without diagnosis) and chapter 18 (symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within R94.0, choose R94.09 (results of other function studies of central nervous system) only when documentation doesn't support a more specific option: electroencephalogram [EEG] (R94.01) and brain scan (R94.02).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 091 (Other Disorders of Nervous System with MCC, relative weight 1.7046), DRG 092 (Other Disorders of Nervous System with CC, relative weight 1.0239) and DRG 093 (Other Disorders of Nervous System without CC/MCC, relative weight 0.7783), in MDC 01 (Diseases and Disorders of the Nervous System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 794.00 (abnormal function study of brain and central nervous system, unspecified) and 794.09 (other nonspecific abnormal results of function study of brain and central nervous system).