Before Assigning ICD-10-CM and ICD-10-PCS Codes Before coding inpatient cases, be sure that you understand how to apply each of the following terms and UHDDS definitions that are explained throughout this lecture: • Principal diagnosis • Secondary diagnosis(es) • Principal procedure • Secondary procedure(s) As you read this lecture, you will notice that: • each type of diagnosis and procedure is defined. • examples of each type of diagnosis and procedure are provided. • an image of an inpatient record face sheet highlights the location of each type of diagnosis and procedure. • images of additional reports from an inpatient record highlight documentation that coders review to assign the most accurate and complete: o diagnosis code(s). o procedure code(s). Admitting Diagnosis The admission diagnosis (or admitting diagnosis ) is the initial diagnosis documented by the: • patient's primary care physician who determined that inpatient care was necessary for: o treatment of a condition diagnosed in the office today (e.g., acute exacerbation of chronic asthma).