Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00–R99) ICD-10-CM
Chapter 18 of the ICD-10-CM classification spans codes R00–R99 and contains 962 diagnosis codes for symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified, of which 773 are billable. The chapter is organized into 14 sections listed below, each linking to its code ranges and individual codes.
Chapter Coding Notes
Note: 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.
Sections in This Chapter 14 ranges · 962 codes
The info icon previews the code ranges inside each row and its instructional notations from the official Tabular List.
About Chapter 18
ICD-10-CM Chapter 18 covers codes from R00 to R99 and is used for documenting symptoms, signs, and abnormal clinical and laboratory findings that cannot be classified under specific diseases.
This chapter provides a range of codes for describing patient conditions when a definitive diagnosis has not been established. It includes various signs like abnormal heart rhythms, unusual results from lab tests, or symptoms such as unexplained weight loss or fever. These codes are essential for cases where healthcare providers need to record observable health issues without attributing them to a clear cause. By capturing this information, clinicians and coders can track patterns of symptoms and pending diagnoses, supporting further evaluation and care planning. This chapter is unique because it focuses on non-specific findings, which reflect the early stages of medical investigation or uncertain clinical status.
Questions About This Page
How many codes are in the R00-R99 range?
The R00-R99 range contains 962 ICD-10-CM diagnosis codes in FY 2026. 773 of them are billable, and the rest are category headers that organize the chapter.
What conditions does R00-R99 cover?
The range covers symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified. The sections listed above break it into groups of related conditions, and each one links to its own page with the full code list.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
