🔍 Chapter 18 · R00-R99

Symptoms & Signs Diagnosis Codes

Symptom codes are used when a definitive diagnosis hasn't yet been established. Codes for chest pain, fatigue, fever, and abnormal test results fall here. These are often used during initial workups before a specific condition is identified.

About This Chapter

Chapter 18 of the ICD-10-CM classification covers symptoms, signs and abnormal clinical and laboratory findings, spanning codes R00-R99. These codes are used by healthcare providers to document diagnoses in your electronic health record (EHR), on insurance claims, and on medical bills.

Why this matters: If you see a code starting with R on your medical bill or health records, it likely falls in this chapter. Understanding what chapter your code belongs to can help you make sense of your diagnosis and ask better questions at your next appointment.