Selecting the correct principal diagnosis is critical--it drives DRG assignment, which in turn affects hospital reimbursement. The principal diagnosis also provides the foundation for coding the patient's case. Accurate selection influences an organization's quality metrics and is necessary for regulatory compliance. If the principal diagnosis is incorrect, it may result in lost revenue or denied claims.
The principal diagnosis is defined in the Uniform Hospital Discharge Data Set (UHDDS) as “that condition established after study to be chiefly responsible for occasioning the admission of the patient to the hospital for care.”
Although this process may seem straightforward, it can be quite complex. AI coding and CDI tools frequently overlook or fail to address these nuances accurately, and even experienced coding and CDI professionals can find this challenging.
Let’s review the key factors and criteria for selecting the principal diagnosis:
Key Factors and Criteria for Assignment
- Review the entire medical record. Comprehensive review of the entire record is crucial for accurate principal diagnosis assignment. In a complex inpatient case, the patient may have many conditions, and the interaction of these conditions will affect principal diagnosis selection.
- Know your coding guidelines. The ICD-10-CM Official Guidelines for Coding and Reporting have specific rules for selecting the principal diagnosis and can be specific to the type of condition being coded. Proper application of principal diagnosis guidelines and rules is essential for accurate principal diagnosis assignment.
- Determine the main focus of treatment. The principal diagnosis represents the main reason a patient was admitted and was central to the care provided. Although various conditions might be treated or briefly mentioned in the records, the principal diagnosis is the condition that necessitated the admission and was the primary focus of treatment.
- Recognize the role of surgical procedures. In most cases, surgery conducted during an inpatient stay determines the principal diagnosis. It is important to know when the procedure does not drive the choice of principal diagnosis.
- Identify co-equal diagnoses. When a patient is admitted for several conditions, choosing which one to assign as the principal diagnosis involves careful thought Consider the circumstances of admission, intensity of treatment, and what resources were used, while still honoring official rules for sequencing. If two or more conditions equally qualify as the principal diagnosis, any one of them may be designated as the principal diagnosis.
- A note about querying. While the physician does not determine the principal diagnosis, they are responsible for providing the documentation to support accurate assignment. Physician queries should be initiated only when clarification is required to resolve unclear, inconsistent, or incomplete documentation.
Correct selection of the principal diagnosis is essential for accurate and defensible coding and billing. Your organization’s revenue cycle is depending on you to get it right.
For education and training on how to appropriately select the principal diagnosis, view our webinar "Selecting the Principal Diagnosis" available in our CDI Pocket Guide Unbound Edition or when you purchase our latest CDI Pocket Guide.
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