2027 ICD-10-CM Diagnosis Code R94.09Abnormal results of other function studies of central nervous system
ICD-10-CM Codes›R00–R99›R90-R94›R94
- Billable — Valid for Submission
- Not Chronic
R94.09 is a billable ICD-10-CM diagnosis code for abnormal results of other function studies of central nervous system. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 91 through 93. As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Abnormal findings without diagnosis.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Abnormal auditory evoked potential
- Abnormal brain stem auditory evoked potential
- Abnormal cerebral evoked potential
- Abnormal nervous system function
- Abnormal results function studies of central nervous system
- Abnormal waves II through V of brainstem AEP
- Auditory evoked potential wave I latency normal with increased latencies - all other waves
- Brainstem auditory evoked potential finding
- Cerebral alteration
- Increased amplitude of cortical somatosensory evoked potential
- Increased latency of brainstem AEP wave I
- Increased neural tube defects detected multiple marker screening
- Increased time interval between wave III-wave V of brainstem auditory evoked potential
- Increased time interval between wave I-wave III of brainstem auditory evoked potential
- Only wave I of brainstem auditory evoked potential seen
- Phase-related abnormality of brainstem AEP
- Raised wave V threshold of brainstem AEP
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to R94.09: its own notes plus those printed at R94, block R90-R94, and Chapter 18. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- abnormal results of radionuclide [radioisotope] uptake studies
- abnormal results of scintigraphy
- 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: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- abnormal findings on antenatal screening of mother (O28.-)
- diagnostic abnormal findings classified elsewhere - see Alphabetical Index
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
Notes
General instructions on how these codes are used.
- This chapter includes symptoms, signs, abnormal results of clinical or other investigative procedures, and ill-defined conditions regarding which no diagnosis classifiable elsewhere is recorded.
- Signs and symptoms that point rather definitely to a given diagnosis have been assigned to a category in other chapters of the classification. In general, categories in this chapter include the less well-defined conditions and symptoms that, without the necessary study of the case to establish a final diagnosis, point perhaps equally to two or more diseases or to two or more systems of the body. Practically all categories in the chapter could be designated 'not otherwise specified', 'unknown etiology' or 'transient'. The Alphabetical Index should be consulted to determine which symptoms and signs are to be allocated here and which to other chapters. The residual subcategories, numbered .8, are generally provided for other relevant symptoms that cannot be allocated elsewhere in the classification.
- The conditions and signs or symptoms included in categories R00-R94 consist of:
- (a) cases for which no more specific diagnosis can be made even after all the facts bearing on the case have been investigated;
- (b) signs or symptoms existing at the time of initial encounter that proved to be transient and whose causes could not be determined;
- (c) provisional diagnosis in a patient who failed to return for further investigation or care;
- (d) cases referred elsewhere for investigation or treatment before the diagnosis was made;
- (e) cases in which a more precise diagnosis was not available for any other reason;
- (f) certain symptoms, for which supplementary information is provided, that represent important problems in medical care in their own right.
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Abnormal, abnormality, abnormalities See Also: Anomaly;
brain R94.09
central NEC R94.09
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Convert R94.09 to ICD-9-CMHistory
Code HistoryHistory
Questions About R94.09Overview
What is the ICD-10 code for abnormal results of other function studies of central nervous system?
The ICD-10-CM code for abnormal results of other function studies of central nervous system is R94.09 (sometimes written as R9409). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is R94.09 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report abnormal results of other function studies of central nervous system on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does R94.09 group to?
When abnormal results of other function studies of central nervous system is the principal diagnosis on an inpatient stay, it groups to MS-DRG 91, 92, 93, with relative weights from 0.7783 to 1.7050 depending on complications. Higher weights mean higher Medicare reimbursement.
Can R94.09 be a principal diagnosis?
Use it with care. This is a symptom code, so once a definitive diagnosis explaining the abnormal results of other function studies of central nervous system is established, that condition takes the principal position instead.
Can R94.09 be reported with a code from O28?
Not as a rule. The Excludes1 note at block R90-R94, which applies to R94.09, lists "abnormal findings on antenatal screening of mother (O28.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
