R94.01 – Abnormal electroencephalogram [EEG]

ICD-10-CM 2027 diagnosis code · Abnormal findings on diagnostic imaging and in function studies, without diagnosis

Billable code

ICD-10-CM code R94.01

Code: R94.01 (claims format: R9401)
Description: Abnormal electroencephalogram [EEG]
Billable: Yes – valid for HIPAA-covered transactions
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 18. Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)
Block: R90-R94 Abnormal findings on diagnostic imaging and in function studies, without diagnosis
Parent codes: R94 › R94.0

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

R94 – Abnormal results of function studies

Includes:

abnormal results of radionuclide [radioisotope] uptake studies
abnormal results of scintigraphy

Block R90-R94

Includes:

nonspecific abnormal findings on diagnostic imaging by computerized axial tomography [CAT scan]
nonspecific abnormal findings on diagnostic imaging by magnetic resonance imaging [MRI][NMR]
nonspecific abnormal findings on diagnostic imaging by positron emission tomography [PET scan]
nonspecific abnormal findings on diagnostic imaging by thermography
nonspecific abnormal findings on diagnostic imaging by ultrasound [echogram]
nonspecific abnormal findings on diagnostic imaging by X-ray examination

Excludes1 (not coded here):

abnormal findings on antenatal screening of mother (O28.-)
diagnostic abnormal findings classified elsewhere - see Alphabetical Index

Index terms for R94.01

Entries in the ICD-10-CM alphabetic index that lead to this code:

Abnormal, abnormality, abnormalities, electroencephalogram [EEG]

Related codes in R94.0

Frequently asked questions

What is ICD-10 code R94.01?

R94.01 is the ICD-10-CM code for abnormal electroencephalogram [EEG], in the block R90-R94 (Abnormal findings on diagnostic imaging and in function studies, without diagnosis).

Is R94.01 a billable code?

Yes. R94.01 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.

What category does R94.01 belong to?

It belongs to category R94 – Abnormal results of function studies.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.