The primary diagnosis refers to the patient's condition that requires the most resources from the provider during the patient's stay. The primary diagnosis is the condition, established after the evaluation, that is primarily responsible for the patient's admission to the hospital. In the uniform set of hospital discharge data (UHDDS), it is defined as the condition “established after a study as primarily responsible for the patient being admitted to the hospital for treatment”. The primary diagnosis describes the underlying cause of a patient's admission to the hospital.
It is assigned after the completion of diagnostic tests and examinations. The primary diagnosis is the primary condition or illness identified by a healthcare provider as the primary reason for a patient's encounter or hospitalization. The official ICD-10 coding and information guidelines describe the primary diagnosis of a health insurance claim as the primary condition responsible for the patient's admission to the hospital, established after a study (i.e., if a patient is admitted for surgery due to an injury but also has diabetes, the injury is the primary diagnosis, while diabetes is secondary because it affects the patient's recovery or treatment, but was not the reason for admission).If a patient has complications, such as sepsis due to surgery, sepsis must be coded as the primary diagnosis and the underlying condition (e.g., unlike the primary diagnosis, which is determined for each visit with a healthcare provider, the primary diagnosis is usually assigned to chronic or ongoing conditions treated by a primary care physician). Despite the slight differences between the primary and primary diagnoses, many health professionals use the term interchangeably.
Precise coding and documentation of the main diagnosis ensures that providers receive adequate reimbursement for the services provided. Coders must be familiar with clinical terminology and understand how each diagnosis affects patient treatment to avoid misclassification. In these cases, the postoperative diagnosis should be listed as the first-list diagnosis because it reflects the most definitive condition after the procedure. For example, in routine antenatal visits without complications, V22.0 or V22.1 can be used as the first diagnosis on the list.
Primary diagnosis is the primary reason a patient seeks medical attention, while secondary diagnoses refer to other conditions that are present but are not the primary reason for the visit or admission. No, chronic diseases should not be the first-list diagnosis unless they are the primary reason for the visit. In addition, in the event of a discrepancy, it will be the diagnosis that comes first according to the ICD-10-CM coding conventions, together with the general and specific ICD-10-CM guidelines for each disease, that will prevail over the guidelines for outpatients. These examples illustrate how the primary diagnosis represents the primary condition or the reason a patient sees a healthcare provider.
Meanwhile, the primary diagnosis describes the condition that is more serious or requires more resources during the hospital stay. If a patient has multiple conditions that require treatment during the same visit or admission, the diagnosis that warrants most of the medical care must be coded as primary.
