Sepsis Coding: Ensuring the Principal Diagnosis Reflects Clinical Reality

Sepsis Coding: Ensuring the Principal Diagnosis Reflects Clinical Reality

By SZ Ahmed, CCS

Sepsis coding remains a high-stakes challenge for health information professionals. Accurate assignment of sepsis as the principal diagnosis (PDX) directly impacts Diagnosis-Related Group (DRG) assignments, reimbursement, and audit outcomes. The first rule of sepsis coding—clinical justification for sepsis as PDX—requires coders to verify its presence on admission (POA) and its role as the primary reason for hospitalization. This article explores this guideline, offering practical examples and strategies to ensure compliance and precision.

the foundation of Sepsis as PDX

Sepsis cannot be assigned as the PDX simply because it appears in the medical record. According to the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) guidelines, sepsis must be POA, supported by clinical documentation (e.g., emergency department [ED] notes, history and physical [H&P], progress notes), and the primary condition prompting admission. If another diagnosis, such as pneumonia or a postoperative infection, better explains the hospitalization, it takes precedence as the PDX.

Coders must dig into the documentation to confirm sepsis was the driving force behind the admission,” says Jane Smith, CPC, a coding consultant with two decades of experience. “Without clear evidence, assigning sepsis as PDX risks DRG errors and audit denials.”

applying the guideline in practice

Real-world coding errors illustrate the importance of this rule. Consider a case where sepsis was initially coded as the PDX but later revised to diverticulitis. Documentation showed sepsis developing on hospital day three (POA=N), with diverticulitis noted in the ED as the admitting condition. Correctly, diverticulitis became the PDX, and sepsis was coded as a secondary diagnosis (SDX), shifting the DRG from 854 (Infectious Diseases) to 329 (Major Small and Large Bowel Procedures). “This correction highlights the need to verify POA status,” Smith notes. “Sepsis arising during the stay cannot be the PDX.”

Conversely, a one-day length-of-stay (LOS) case demonstrated appropriate sepsis coding. The ED documented sepsis as the admitting diagnosis for a patient with fever and hypotension, supported by progress notes and aggressive treatment with antibiotics and fluids. Sepsis was correctly assigned as the PDX (A41.9, Sepsis, unspecified organism), with pneumonia as an SDX, yielding DRG 871 (Septicemia or Severe Sepsis without Mechanical Ventilation >96 Hours with Major Complication or Comorbidity). “When documentation aligns from the start, sepsis as PDX is defensible,” says Michael Lee, RHIA, a compliance officer.

practical Scenarios for Coders

Correct PDX assignment hinges on answering, “Why was the patient admitted?” Two scenarios clarify this process.

In the first, a patient presents to the ED with chills, hypotension, and altered mental status. The ED note states, “Admit for sepsis, likely from urinary tract infection.” Treatment includes broad-spectrum antibiotics, IV fluids, and lactate testing. Coding assigns A41.9 (Sepsis, unspecified organism) as the PDX and N39.0 (Urinary tract infection) as an SDX, resulting in DRG 871. This is appropriate, as sepsis was POA and the primary focus of care.

In contrast, a patient admitted for an infected surgical wound post-cholecystectomy develops sepsis on day three. No sepsis is mentioned in the ED or H&P, and progress notes confirm its onset during hospitalization (POA=N). Coding assigns T81.4XXA (Infection following a procedure) as the PDX and A41.9 (Sepsis) as an SDX, adjusting the DRG to reflect a postoperative complication. This ensures accuracy, as sepsis was not the admitting condition.

Missteps in sepsis coding can lead to incorrect DRG assignments, reduced reimbursement, or audit scrutiny. Coders should prioritize reviewing ED notes, H&P, and early progress notes to establish POA and clinical justification. “If sepsis is treated aggressively from admission and no other condition better explains the stay, it’s likely the PDX,” Lee advises. Collaboration with providers to clarify documentation, especially when sepsis onset is ambiguous, further strengthens coding accuracy.

By adhering to this foundational guideline, coders can ensure sepsis coding reflects the true clinical picture, supporting both compliance and optimal reimbursement.