Diagnosis

The act or process of identifying or determining the nature and cause of a disease or injury through evaluation of patient history, examination of a patient, and review of laboratory data. Diagnoses in the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey are abstracted from medical records. Before 2016, diagnoses were coded according to the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD–9–CM). Starting with 2016 data, diagnosis data were classified using International Classification of Diseases, 10th Revision, Clinical Modification (ICD–10–CM). (Also see Sources and Definitions, International Classification of Diseases, Clinical Modification [ICD–CM].)

For a given medical care encounter, the first-listed diagnosis can be used to categorize the visit, or if more than one diagnosis is recorded on the medical record, the visit can be categorized based on all diagnoses recorded. Analyzing first-listed diagnoses avoids double-counting events such as visits or hospitalizations; the first-listed diagnosis is often, but not always, considered the most important or dominant condition among all comorbid conditions. However, the choice of the first-listed diagnosis by the medical facility may be influenced by reimbursement or other factors. (Also see Sources and Definitions, External cause of injury; Injury; Injury-related visit.)