Principal Diagnosis

What is a principal diagnosis?

A principal diagnosis describes the underlying cause of a patient’s hospital admission. It is assigned after completing diagnostics tests and examinations.

Occasionally, complications or serious events take place during the patient’s stay. For example, if a patient acquires a hospital associated infection post-operation. In this case, the more resource-intensive condition, in terms of treatment length and aggressiveness, is called the primary diagnosis.

Why is a principal diagnosis an important metric in healthcare?

Principal diagnosis serves an important function in determining which diagnosis-related group (DRG) code to assign a patient. DRGs and other diagnostic codes, like ICD-10, are not only used to electronically record a patient’s treatment history, but they also play a crucial role in healthcare billing.

Healthcare providers will use these codes to determine the complexity of patient treatment. This includes the symptoms they initially presented and any medications, treatments, or procedures they received.

What is the difference between a principal diagnosis vs primary diagnosis?

The ICD-10 Official Guidelines for Coding and Reporting describes the principal diagnosis for a health insurance claim as the condition chiefly responsible for admission of the patient to the hospital, established after study (i.e. evaluation and diagnostics). Specifically for inpatient stays, a principal diagnosis is used to categorize and assign a diagnosis-related group (DRG) to the patient.

Meanwhile, a primary diagnosis describes the condition that is most serious or resource-intensive during the inpatient stay. The principal and primary diagnosis are often the same but they can differ. Despite the slight differences between principal and primary diagnosis many healthcare professionals use the term interchangeably.