Report Signs and Symptoms for This Swollen Knee Presentation
Question: A provider’s documentation says an established patient presented with right knee pain and swelling that developed while working outdoors over a period of several weeks, cutting trees and dragging brush. The patient did not recall a specific injury, just that their knee has been hurting. Examination showed a right knee effusion. Because of the patient’s occupational tick exposure and the differential diagnosis for an atraumatic effusion, the provider ordered Lyme serology and right-knee radiographs to be completed at other facilities. The encounter lasted 20 minutes. How do I code this? Vermont Subscriber Answer: When coding the provision of care, you’ll look to an evaluation and management (E/M) code. Because the provider documented 20 minutes of total time on the date of the encounter, report 99213 (Office or other outpatient visit for the evaluation and management of an established patient, which requires a medically appropriate history and/or examination and low level of medical decision making. When using total time on the date of the encounter for code selection, 20 minutes must be met or exceeded.). For the diagnosis coding, you’ll be reporting signs and symptoms, according to Section IV of the FY 2026 ICD-10-CM Official Guidelines, as the provider hasn’t recorded any confirmed diagnoses. Accordingly, you’ll report ICD-10-CM code M25.461 (Effusion, right knee) for the documented effusion. You may also report M25.561 (Pain in right knee) if the provider separately evaluates or manages the pain and it is not considered integral to the effusion. Although the provider is evaluating the patient for Lyme disease, the environmental exposure to ticks and lab orders establish Lyme as a differential diagnosis rather than a confirmed infection. Do not report Lyme disease unless the provider establishes the diagnosis after considering the clinical findings and test results. Similarly, it wouldn’t be appropriate to report any injury or arthritis codes without the provider diagnosing those conditions — the ordering of the X-rays is not sufficient to report them. Rachel Dorrell, MA, MS, CPC-A, CPPM, Production Editor, AAPC
