Chapter 18

R00–R99: Symptoms, Signs and Abnormal Clinical and Laboratory Findings

Symptoms, Signs and Abnormal Clinical and Laboratory Findings diagnostic classification updated for 2026.

Chapter Instructions

Excludes2(Not included here. Code separately if applicable.)
  • 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)
Internal Codes
  • R94.5|

    Abnormal results of liver function studies

  • R94.6|

    Abnormal results of thyroid function studies

  • R94.7|

    Abnormal results of other endocrine function studies

  • R94.8|

    Abnormal results of function studies of other organs and systems

  • R97|

    Abnormal tumor markers

  • R97.0|

    Elevated carcinoembryonic antigen [CEA]

  • R97.1|

    Elevated cancer antigen 125 [CA 125]

  • R97.2|

    Elevated prostate specific antigen [PSA]

  • R97.20|

    Elevated prostate specific antigen [PSA]

  • R97.21|

    Rising PSA following treatment for malignant neoplasm of prostate

  • R97.8|

    Other abnormal tumor markers

  • R99|

    Ill-defined and unknown cause of mortality

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