In severe sepsis coding, what must be coded first?

When coding for severe sepsis, the underlying infection is the primary focus because it represents the condition that has led to the patient's severe systemic response, which is characterized by sepsis. The ICD-10-CM guidelines specify that the underlying infection must be sequenced before coding for the severe sepsis itself. This is crucial because it allows healthcare providers and insurers to understand the etiology of the sepsis and to properly assess the patient's overall health status and the nature of the problem being treated.

In the case of severe sepsis, the underlying infection could be a pneumonia, urinary tract infection, or other severe localized infections that have triggered the acute physiological changes associated with sepsis. Coding this first accurately captures the primary reason for the severe sepsis diagnosis and forms the basis for further coding of sepsis-related complications.

Following the coding of the underlying infection, severe sepsis is then coded to indicate the severity and the clinical implications that arise due to the systemic response. By prioritizing the underlying infection, coders align with the ICD-10-CM coding rules, ensuring that the medical necessity is clearly documented and supported.