Sometimes, distinguishing between primary, principal, and secondary diagnoses can be challenging, especially when navigating the complexities of medical coding and clinical documentation improvement (CDI). This article aims to clarify these concepts, focusing particularly on Secondary Diagnosis Examples, to help healthcare professionals and CDI specialists improve their understanding and accuracy.
To effectively differentiate, it’s crucial to understand the definitions of each diagnosis type individually. Often, the terms “primary diagnosis” and “principal diagnosis” are used interchangeably, leading to confusion. Let’s break down each term:
Primary Diagnosis: Clarifying its Role
The primary diagnosis is frequently mistaken for the principal diagnosis, especially in inpatient settings. In reality, the primary diagnosis refers to the condition that demanded the most resources or was the most serious during a patient’s hospitalization or inpatient encounter. While often the primary and principal diagnoses are the same, this isn’t always the case.
Principal Diagnosis: The Reason for Admission
The principal diagnosis, as defined by the ICD-10-CM Official Guidelines for Coding and Reporting, is the condition that, after study, is determined to be the main reason for the patient’s admission to the hospital. It’s vital to remember that the principal diagnosis isn’t necessarily what initially brought the patient to the emergency room but rather the condition that necessitated the inpatient admission.
Consider a patient who presents to the emergency department with dehydration and is subsequently admitted for gastroenteritis. In this scenario, gastroenteritis is the principal diagnosis. It’s often described as the diagnosis that “bought the bed,” meaning it’s the condition that led the physician to decide inpatient care was necessary. A key question for CDI specialists to consider when reviewing a medical record is: “What diagnosis was significant enough to require inpatient care?”
It’s important to note that the physician doesn’t have to explicitly state the condition in the history and physical (H&P) as the principal diagnosis. However, the symptoms that prompted the admission must be clearly linked to the final diagnosis by the physician. Coders are not permitted to infer cause-and-effect relationships, as emphasized by the AHA’s Coding Clinic. The principal diagnosis is determined “after study,” acknowledging that the definitive diagnosis may only be established after a thorough workup.
Differentiating Primary and Principal Diagnosis: An Example
Let’s illustrate the difference between primary and principal diagnoses with an example. Imagine a patient admitted for a scheduled total knee replacement due to osteoarthritis. While in the pre-operative holding area, preparing for surgery, the patient suffers a ST-segment elevation myocardial infarction (STEMI). The planned knee replacement is postponed, and the patient is immediately taken to the cardiac catheterization lab for stent placement.
In this case, to determine the principal diagnosis, we ask: What condition occasioned the admission? The answer is osteoarthritis. This is the diagnosis that led to the hospital admission and the need for an inpatient bed.
Now, to identify the primary diagnosis, we consider: Which diagnosis led to the majority of resource utilization? In this scenario, it’s the acute myocardial infarction (STEMI). However, STEMI cannot be the principal diagnosis because it was not the “condition that occasioned the admission.”
Secondary Diagnosis: Understanding “Other Diagnoses”
Now, let’s delve into secondary diagnoses. The Uniform Hospital Discharge Data Set (UHDDS) defines “other diagnoses,” or secondary diagnoses, as conditions that either coexist at the time of admission or develop subsequently and affect patient care during the current episode of care. A helpful way to think of secondary diagnoses is as the patient’s “baggage”—conditions they bring with them or develop during their stay that must be considered in managing their principal diagnosis.
For example, consider our patient admitted for osteoarthritis and a total knee replacement. Suppose this patient also has a history of type 2 diabetes, chronic obstructive pulmonary disease (COPD), and coronary artery disease (CAD). These pre-existing conditions, while not the reason for admission, are secondary diagnoses. They require management and monitoring throughout the hospital stay because they impact the patient’s overall care and recovery from the knee replacement.
Furthermore, conditions that develop after admission and influence patient care during the current stay are also classified as secondary diagnoses. In our example, the acute STEMI, which occurred after admission, becomes a secondary diagnosis as it requires immediate and significant medical intervention during this hospitalization.
Criteria for Identifying Secondary Diagnoses
For a condition to be classified as a secondary diagnosis, it must meet at least one of the following criteria:
- Clinical evaluation
- Therapeutic treatment
- Diagnostic studies
- Extended length of hospital stay
- Increased nursing care and/or monitoring
Navigating Complex Scenarios: Multiple Acute Issues
Identifying principal and secondary diagnoses can become complex when a patient is admitted with multiple acute conditions present on admission, such as a patient admitted with both aspiration pneumonia and an acute cerebrovascular accident (CVA). In such cases, specific coding guidelines provide direction. Refer to the 2017 Official Guidelines for Coding and Reporting for detailed guidance.
In situations like the aspiration pneumonia and acute CVA example, determining the principal diagnosis can be challenging as both conditions could independently necessitate inpatient admission and meet medical necessity criteria. If it’s determined that either condition could equally be the reason for admission, the Official Guidelines for Coding and Reporting allow for either to be selected as the principal diagnosis. However, if the medical record doesn’t clearly indicate the conditions’ equal contribution to the admission, or if clarification is needed, querying the provider for the diagnosis that led to the admission is recommended.
Conclusion: Accurate Diagnosis Coding for Effective CDI
Understanding the nuances between primary, principal, and secondary diagnoses, particularly recognizing secondary diagnosis examples, is fundamental for accurate medical coding and effective Clinical Documentation Improvement practices. By applying these definitions and guidelines, healthcare professionals can ensure precise coding, reflecting the complete clinical picture of the patient’s encounter and supporting appropriate reimbursement and quality reporting.
