Two codes are required for severe sepsis in ICD-10-CM: the underlying infection and the sepsis itself

Outline in brief

• Hook: a quick, relatable question about coding severe sepsis

• Core idea: you need two codes—one for the underlying infection, one for the severe sepsis itself

• Why it matters: clear documentation, accurate data, proper treatment reflection, better reimbursement

• Concrete examples: pneumonia with severe sepsis; UTI with severe sepsis; abdominal source with severe sepsis

• Practical tips: how to document, how to assign codes, common traps

• Gentle wrap-up: a simple recap and a nudge toward solid record-keeping

Two codes, not two mysteries: the essential rule for severe sepsis coding

Here’s the thing about severe sepsis: it isn’t just a single label you can slap on a chart and call it a day. It’s a condition built from two critical pieces that need to be captured distinctly in the medical record. And yes, that means two codes. The first code goes to the underlying infection—the source that sparked the sepsis. The second code names the severe sepsis itself. Think of it as tagging both the root cause and the clinical consequence so the whole story is on one page.

Let me explain why this matters beyond just ticking boxes. When you code the underlying infection, you’re signaling where the infection started—pneumonia, a urinary tract infection, an abdominal source, or something else. That source matters not only for the doctor’s notes but for treatment decisions, infection control, and even public health data. Then you add the severe sepsis code, which communicates the systemic response, the seriousness of the patient’s condition, and the intensity of the care provided. Put together, these two codes create a complete clinical picture. Without both, the record can look incomplete, and that can ripple through to data quality, quality measures, and reimbursements.

The rule in plain terms: document both the infection and the sepsis. That pairing is not a preference; it’s a guideline. If you only code the sepsis and skip the infection, you risk losing the clinical nuance that explains why sepsis occurred and how it progressed. If you only code the infection, you miss the escalation to severe sepsis and the level of care required. Patients deserve a record that reflects the full journey—source, progression, and response to treatment.

What counts as the “underlying infection”?

The first code should reflect the source of the sepsis. Common sources you’ll encounter include:

• Pneumonia (the lungs become the battleground)

• Urinary tract infection (often a route for bacteria to enter the bloodstream)

• Abdominal source (peritonitis, biliary infections, diverticulitis, and the like)

• Skin or soft tissue infections that spread systemically

Clinically, you’ll often see a chart note that says something like, “Severe sepsis due to pneumonia” or “Severe sepsis secondary to UTI.” The key is to capture the root cause with a code that denotes the infection’s location or origin. This is the piece that helps clinicians track how the infection began and informs decisions about antibiotics, source control, and additional investigations.

What counts as the “severe sepsis” code?

The second code names the severity: severe sepsis itself. This code flags that the body’s response to infection has become life-threatening, requiring closer monitoring, aggressive therapy, and often admission to a higher level of care. In many coding guidelines, the severe sepsis code accompanies the infection code to convey the full clinical picture. In other words, you’re documenting that the patient isn’t just fighting an infection—this infection has escalated into a systemic, life-threatening process.

Why this dual coding approach matters for data and care

Documentation accuracy isn’t a dry, boring detail. It’s how the system knows how to allocate resources, measure outcomes, and track the effectiveness of treatments. Two codes for severe sepsis:

• Improves data quality: coding both the source and the severity gives a clearer snapshot of the patient’s condition and the care delivered.

• Supports treatment records: the documentation now aligns with the clinical story—where the infection started and how severe the reaction was.

• Affects reimbursement and reporting: insurers and payers rely on precise coding to understand why a patient required intensive care, antibiotic therapy, and extended hospitalization.

• Enhances research and quality metrics: robust data on severe sepsis outcomes helps hospitals monitor and improve sepsis care pathways.

A few practical examples to ground this

Example 1: Pneumonia with severe sepsis

• Underlying infection: pneumonia code (reflecting the lung infection)

• Severe sepsis: the separate code for severe sepsis

In the medical record, you’d see notes about chest imaging, a bacterial pneumonia diagnosis, blood cultures, and escalation to ICU care. The two-code approach ensures the pivot point—the infection source—and the severity are both captured.

Example 2: Urinary tract infection with severe sepsis

• Underlying infection: UTI code (or pyelonephritis, if applicable)

• Severe sepsis: the sepsis severity code

Here, the chart would show urinary symptoms, positive cultures, and evidence of systemic involvement such as high fever, elevated heart rate, or organ dysfunction. The coding mirrors that clinical story.

Example 3: Abdominal source with severe sepsis

• Underlying infection: code for an abdominal source (e.g., diverticulitis or peritonitis)

• Severe sepsis: the sepsis severity code

Abdominal infections often involve aggressive fluid resuscitation, antibiotics, and sometimes surgery. Again, the two codes map to what’s happening in real life.

Two codes, two truths: a gentle reminder for coders-in-progress

• Documentation is king: the chart should clearly indicate both the infection source and the severe sepsis. If a note mentions “severe sepsis due to pneumonia,” make sure the pneumonia code is present alongside the severe sepsis code.

• Sequencing matters: generally, the infection code comes first, followed by the severe sepsis code. The exact sequencing can depend on the coding guidelines you’re using, but the principle stays the same—first the source, then the severity.

• Don’t overlook the clinical picture: even when the infection is obvious, clinicians may document additional details—like septic shock—that could affect code selection. If septic shock is present, there may be a separate code for that condition as well, and you’ll want to follow the official guidance for how to layer codes without overcoding.

Pitfalls to watch for (and how to avoid them)

• Missing the infection source: it’s easy to stop at “severe sepsis” and forget the underlying source. Always look for the origin in the documentation.

• Coding the wrong severity: severe sepsis is distinct from septic shock. If the chart mentions septic shock, you’ll need to capture that specifically as well, using the appropriate codes and sequence.

• Relying on a single line: some notes say “sepsis with severe sepsis” or just “sepsis.” The record should clearly separate the infection source and the severe sepsis code so the patient’s story isn’t tangled or ambiguous.

• Incomplete documentation: a well-documented chart should spell out both the source and the severity. If the documentation is sparse, ask clarifying questions or review the patient’s tests and treatments to confirm the coding path.

A few tangible tips for smoother coding days

• Read the notes with a detective’s eye: find the infection source, then verify whether the clinician noted “severe sepsis” as a separate diagnosis or if the chart implies a severe systemic response.

• Use the patient’s test results as anchors: cultures, imaging results, and signs of organ dysfunction help confirm both the source and the severity.

• Keep a simple checklist in your coding pad: source infection code, severe sepsis code, and any other related considerations (like septic shock, if documented).

• When in doubt, document the rationale: a brief note in the chart that explains why two codes are needed can prevent confusion later on.

A quick recap you can carry in your head

• Severe sepsis requires two codes: one for the underlying infection (the source) and one for the severe sepsis itself.

• The purpose is to reflect the full clinical picture—where the infection started and how severely the body is reacting.

• Good documentation supports accurate coding, better data, and proper reimbursement.

• Watch for common traps: missing the infection source, mislabeling severity, or skipping connections between notes and codes.

Closing thought: the elegance of the two-code approach

Coding severe sepsis isn’t about adding more numbers to a chart. It’s about telling a complete, honest story of a patient’s illness. The two-code method bridges that story—the source of infection and the storyline of severity—so everyone who touches the record, from frontline clinicians to hospital administrators, reads the same clear tale. When you code with that mindset, you’re not just tagging data—you’re helping care teams tailor treatment, support patient outcomes, and keep the record straight from admission to discharge.

If you ever pause at this crossroads, ask yourself: what started the clock, and how severely did it run? Answer those two questions, and you’ll have the two-code solution in hand—simple, precise, and true to the patient’s journey.