Some guidelines for coding include not assigning additional codes to conditions that are necessary to diagnose a disease and not using a symptom as a primary diagnosis in place of a malignancy, according to the American Health Information Management Association. In an inpatient setting, if a diagnosis is possible or questionable, coding professionals should code it as if it exists. In an outpatient setting, if a diagnosis is possible, they should code it as if it does not exist.
When a patient is receiving a diagnostic service in an outpatient setting, the order of diagnostic codes should be diagnosis, condition, and then problem or reason for seeking medical help, reports the American Health Information Management Association. Also in the outpatient setting, coding professionals should code for the doctor's interpretation of a test. If a doctor examines tissue and diagnoses it as a carcinoma, it is important to apply the code for carcinoma as it is a definitive diagnosis. However, in a test such as a urinalysis, where a doctor does not interpret the results, coding professionals should not code for the diagnosis until a physician has made a definitive confirmation. Codes that cover symptoms are acceptable if there is not a diagnosis from a physician.