2027 ICD-10-CM Diagnosis Code R29.818Other symptoms and signs involving the nervous system

ICD-10-CM Codes›R00–R99›R25-R29›R29

ICD-10-CM R29.818
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

R29.818 is a billable ICD-10-CM diagnosis code for other symptoms and signs involving the 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 Nervous system signs and symptoms.

Code Identity

ICD-10-CM Code
R29.818
Billable Status
Yes — Valid for Submission
Code Describes
Other symptoms and signs involving the nervous system
Short Description
Other symptoms and signs involving the nervous system
Same as the full description in the CMS dataset.
Parent Code
R29.81
Other symptoms and signs involving the nervous system

Code Classification

ChapterR00–R99Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
SectionR25-R29Symptoms and signs involving the nervous and musculoskeletal systems
CategoryR29Other symptoms and signs involving the nervous and musculoskeletal systems
This CodeR29.818Other symptoms and signs involving the nervous system

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormal neurovascular status of distal limb
  • Abnormality of myotome
  • Absence of receptor sites
  • Alopecia, progressive neurological defect, endocrinopathy syndrome
  • Alteration in tissue perfusion
  • Arthropathy of the elbow associated with a neurological disorder
  • Autosomal recessive cerebellar ataxia, pyramidal signs, nystagmus, oculomotor apraxia syndrome
  • Barany's sign
  • Barber's chair sign
  • Barber's chair sign positive
  • Bilateral deficit of nervous system structures
  • Brudzinski's sign positive
  • Bulbar neurological symptom
  • Bulging fontanelle
  • Cerebrospinal fluid flow finding
  • Chvostek sign positive
  • Congenital nystagmus
  • Congenital nystagmus with sensory abnormality
  • Cord sign
  • Crossed laterality
  • Decrease in receptor sites
  • Decreased intracranial pressure adaptive capacity
  • Decreased pain threshold
  • Difficulty accepting base of support
  • Difficulty performing oral motor functions
  • Does not accept base of support
  • Does not move blade of tongue
  • Does not perform oral motor functions
  • Effects of lightning
  • Empty delta sign
  • Extrapyramidal sign
  • Filling defect
  • Finding of intracranial pressure
  • Finding related to ability to accept base of support
  • Finding related to ability to move blade of tongue
  • Finding related to neurovascular status of limb
  • Flail arm
  • Flail motion
  • Fluctuation of cerebral spinal fluid
  • Froment's sign positive
  • Hippocampal pressure groove
  • Hoover sign of lower limb
  • Impaired peripheral neurovascular function
  • Increase in receptor sites
  • Ineffective tissue perfusion
  • Inequality in size of cerebral ventricles
  • Kernig's sign positive
  • Level of fontanelle - finding
  • Long tract sign
  • Low pain threshold
  • Midline shift of brain
  • Named sensory sign
  • Neck pain co-occurrent with neurological deficit following whiplash injury to neck
  • Nervous system problem
  • Neurodisability
  • Neurological complication following vaccination
  • Neurological deficit
  • Neurological disorder due to obesity
  • Neurological disorder monitoring status
  • Neurological drug side effects
  • Neurological injury from lightning
  • Neurological symptom
  • Neuronal depopulation
  • Neurovascular deficit
  • No reactive accommodation reflex
  • Orthostatic intolerance
  • Pain threshold - finding
  • Past pointing present
  • Piebald trait with neurologic defects syndrome
  • Pronator drift
  • Pseudoparalysis
  • Pseudoparalysis due to generalized arthritis
  • Pyramidal sign
  • Receptor site alteration
  • Reduced flow of cerebrospinal fluid
  • Romberg's sign positive
  • Spinal atrophy, ophthalmoplegia, pyramidal syndrome
  • Surface receptor redistribution
  • Tinel's sign positive
  • Transient monoplegia
  • Unable to accept base of support
  • X-linked intellectual disability with hypogammaglobulinemia and progressive neurological deterioration syndrome

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to R29.818: its own notes plus those printed at Chapter 18. A note printed at a category, block or chapter applies to every code under it.

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.

From Chapter 18 (R00-R99) Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified applies to 774 codes
  • abnormal findings on antenatal screening of mother (O28.-)
  • certain conditions originating in the perinatal period (P04-P96)
  • signs and symptoms classified in the body system chapters
  • signs and symptoms of breast (N63, N64.5)

Notes

General instructions on how these codes are used.

From Chapter 18 (R00-R99) Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified applies to 774 codes
  • 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.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR SYM010
Nervous system signs and symptoms
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Neurologic Diseases

The brain, spinal cord, and nerves make up the nervous system. Together they control all the workings of the body. When something goes wrong with a part of your nervous system, you can have trouble moving, speaking, swallowing, breathing, or learning. You can also have problems with your memory, senses, or mood.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert R29.818 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
781.99 Nerve/musculskel sym NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About R29.818Overview

What is the ICD-10 code for other symptoms and signs involving the nervous system?

The ICD-10-CM code for other symptoms and signs involving the nervous system is R29.818 (sometimes written as R29818). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is R29.818 (Other symptoms and signs involving the nervous system) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other symptoms and signs involving the nervous system on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does R29.818 group to?

When other symptoms and signs involving the 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 R29.818 be a principal diagnosis?

Use it with care. This is a symptom code, so once a definitive diagnosis explaining the other symptoms and signs involving the nervous system is established, that condition takes the principal position instead.

What is the ICD-9 equivalent of R29.818?

Under the General Equivalence Mappings, other symptoms and signs involving the nervous system converts to ICD-9-CM 781.99 (nerve/musculskel sym NEC). The mapping is approximate, so confirm the match fits the documentation.