7.1 Sepsis, Severe Sepsis, Postoperative and Other Infections

7.1 Sepsis, Severe Sepsis, Postoperative and Other Infections

Quick Answer: Sepsis-3 is infection plus acute organ dysfunction (a Sequential Organ Failure Assessment (SOFA) rise of 2 or more). Systemic inflammatory response syndrome (SIRS) is not the Sepsis-3 definition. Urosepsis is nonspecific and has no default ICD-10-CM code. Severe sepsis (subcategory R65.2-) needs organ dysfunction linked to sepsis; do not assign it when organ failure is attributed to another cause. Septic shock is circulatory failure with sepsis and must be documented. Postoperative infection requires a provider-stated causal relationship. Do not merge the Centers for Medicare & Medicaid Services (CMS) hospital-acquired condition (HAC) payment provision with the HAC Reduction Program.

This independent OpenExamPrep section helps inpatient clinical documentation integrity (CDI) specialists study infectious-disease documentation under the Inpatient Prospective Payment System (IPPS). It is not an Association of Clinical Documentation Integrity Specialists (ACDIS) product and does not claim ACDIS approval, partnership, or exact equivalence with ACDIS materials.

Two languages: Sepsis-3 at the bedside, ICD-10-CM in the record

The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3, Singer and colleagues, 2016) define sepsis as life-threatening organ dysfunction caused by a dysregulated host response to infection. Organ dysfunction is operationalized as an acute increase in the SOFA score of 2 or more. Clinical septic shock in that framework is a subset of sepsis with circulating and cellular or metabolic abnormalities, often recognized when vasopressors are required to keep mean arterial pressure at or above 65 mmHg and lactate remains above 2 mmol/L after adequate volume resuscitation. Those thresholds help you read a chart. They are not ICD-10-CM codes, and they are not a license for the CDI specialist to assign sepsis.

SIRS—fever or hypothermia, tachycardia, tachypnea, abnormal white-cell count—was central to older Sepsis-1 and Sepsis-2 constructs. SIRS is not the Sepsis-3 definition. A patient can meet SIRS criteria with pancreatitis, trauma, or a cytokine infusion and have no infection. A frail older adult can be septic with a blunted white-cell response and no fever. Domain II items test whether you treat SIRS boxes, a lactate value, and a SOFA calculator as clinical indicators that support a query, not as a substitute for a provider diagnosis.

Quick SOFA (qSOFA)—altered mentation, respiratory rate of 22 or greater, systolic blood pressure of 100 mmHg or less—is a bedside screen. It is not the Sepsis-3 definition and it is not a code.

SOFA components that show up as indicators include PaO2/FiO2, platelets, bilirubin, mean arterial pressure or vasopressor dose, Glasgow Coma Scale, and creatinine or urine output. An electronic SOFA of 4 is still an indicator. The treating provider names sepsis, severe sepsis, or shock.

ICD-10-CM Official Guidelines for Coding and Reporting (FY 2026, section I.C.1.d) still speak the language of sepsis, severe sepsis, and septic shock. For a diagnosis of sepsis, assign the code for the underlying systemic infection (a specified organism when documented, or A41.9, Sepsis, unspecified organism, when it is not). A code from subcategory R65.2, Severe sepsis, is not assigned unless severe sepsis or associated acute organ dysfunction is documented. Negative or inconclusive blood cultures do not preclude sepsis when the provider has diagnosed it; query if the diagnosis and the microbiology story conflict.

Urosepsis is not a code

Urosepsis is a nonspecific term. The Official Guidelines state that it is not synonymous with sepsis and has no default code in the Alphabetic Index. If a provider writes only urosepsis, query. Clinically valid options might include urinary tract infection without sepsis, sepsis due to a urinary source, pyelonephritis, another specified infection, and Other, please specify. Do not silently translate urosepsis into A41.9. Do not offer hypernatremia, or any other option the labs do not support, just to fill a template.

Severe sepsis: linkage is the exam item

If the patient has sepsis and associated acute organ dysfunction, or multiple organ dysfunction, follow the instructions for coding severe sepsis. Coding severe sepsis requires a minimum of two codes: first the underlying systemic infection, then R65.20 (severe sepsis without septic shock) or R65.21 (severe sepsis with septic shock). Additional codes for each associated acute organ dysfunction are also required. A code from R65.2- can never be the principal diagnosis.

The high-risk trap is linkage. If the record says the acute organ dysfunction is related to a medical condition other than the sepsis, do not assign R65.2-. An acute kidney injury attributed solely to ureteral obstruction, cardiogenic shock attributed solely to ST-elevation myocardial infarction, or respiratory failure attributed solely to flash pulmonary edema is not automatically severe sepsis because the word sepsis also appears. An acute organ dysfunction must be associated with the sepsis in order to assign the severe sepsis code. If documentation is not clear whether the organ dysfunction is related to the sepsis or to another condition, query the provider. Do not complete severe sepsis from a SOFA of 4 plus a positive urinalysis.

Septic shock in the Official Guidelines refers to circulatory failure associated with severe sepsis and therefore represents a type of acute organ dysfunction. Sequence the systemic infection first, then R65.21, or T81.12- when the shock is postprocedural septic shock. Do not assign R65.21 as principal. Do not infer septic shock from a norepinephrine infusion alone. Vasopressors are indicators. The provider must document septic shock, or postprocedural septic shock, before that construct is reported.

When severe sepsis is present on admission and meets the definition of principal diagnosis, the underlying systemic infection is principal, followed by R65.2-. When severe sepsis develops during the encounter, the infection and R65.2- are secondary diagnoses. Severe sepsis may be present on admission even if the label is confirmed later; if present-on-admission (POA) status is unclear, query. POA = Y means present at the inpatient order; N not present; U insufficient documentation; W clinically undetermined. Conditions that arise in the emergency department, observation, or outpatient surgery before the inpatient order are POA = Y.

If the reason for admission is sepsis or severe sepsis and a localized infection such as pneumonia or cellulitis, the systemic infection is sequenced first and the localized infection is secondary. If the patient is admitted with a localized infection and sepsis develops later, the localized infection is first.

Postoperative infection versus HAC and surgical-site infection

Postprocedural complication codes rest on the provider’s documentation of the relationship between the infection and the procedure. CDI does not assign postoperative infection because a wound looks red on day five. Query for the relationship when indicators exist: purulence, bedside wound exploration, antibiotics directed at the operative site, or a surgeon’s statement that the infection is related to the anastomosis or implant.

For sepsis following a surgical-site infection, the Official Guidelines sequence the infection-following-procedure code that identifies the site (T81.41 through T81.43, T81.49, or obstetric equivalents) first when the site is known, then sepsis following a procedure (T81.44), the organism, and R65.2- if severe sepsis is documented. If a postprocedural infection results in postprocedural septic shock, assign T81.12- and do not also assign R65.21.

Keep two CMS constructs separate. The HAC payment provision is fourteen CMS categories on the claim. When a listed condition is not present on admission, POA = N or POA = U generally prevents that condition from acting as a complication or comorbidity (CC) or major CC (MCC). POA = W is paid like Y. Infection-related payment-provision categories include vascular catheter-associated infection; catheter-associated urinary tract infection (CAUTI); surgical-site infection (SSI) mediastinitis after coronary artery bypass grafting; SSI after bariatric surgery; SSI after certain orthopedic procedures (spine, neck, shoulder, elbow); and SSI after a cardiovascular implantable electronic device. The HAC Reduction Program is a different mechanic: a 1 percent cut for hospitals in the worst Total HAC Score quartile. Its infection measures are National Healthcare Safety Network (NHSN) healthcare-associated infections—central line-associated bloodstream infection, CAUTI, colon and abdominal hysterectomy SSI, methicillin-resistant Staphylococcus aureus bacteremia, and Clostridioides difficile infection—plus Patient Safety Indicator 90. Colon SSI is an NHSN measure in the Reduction Program. It is not a blanket rule that every SSI is one of the fourteen payment-provision categories.

Never put HAC, diagnosis-related group, or quality-outcome language in a query. The August 2026 ACDIS/AHIMA Guidelines for Achieving a Compliant Query Practice require sourced clinical indicators, clinically relevant options, a required open-ended Other, please specify (or similar), independent provider judgment, and no reimbursement wording. Yes/no queries may not introduce a new diagnosis.

Bacterial and viral infections that never become sepsis still matter. Organism specificity (for example, methicillin-resistant Staphylococcus aureus versus influenza) changes pneumonia and infection codes and can change grouping. Query the source and organism when cultures or multiplex panels support it, and do not default every positive culture to sepsis. A postoperative wound infection is not automatically severe sepsis, an HAC, or an NHSN surgical-site infection label.

Exam-style scenarios

Scenario: urosepsis and a SOFA rise. Ms. P., 68, is admitted from the emergency department at 01:40 with fever, hypotension that responds to fluids, pyuria, and confusion. The emergency physician writes urosepsis. SOFA rises by 3 because of creatinine and Glasgow Coma Scale. Blood cultures remain negative. The hospitalist copies urosepsis on day two. CDI does not assign sepsis or severe sepsis from the SOFA widget. A multiple-choice query offers urinary tract infection without sepsis, sepsis of urinary origin, pyelonephritis, other specified infection, and Other, please specify. Cite the fever, pyuria, hypotension, and mental-status change. Do not mention case mix.

Scenario: organ failure with another cause. Mr. D. has documented E. coli sepsis. Acute kidney injury is present. Urology documents complete ureteral obstruction from a stone as the sole cause of the kidney injury and states it is not septic nephropathy. Do not assign R65.2- on the strength of that kidney injury. If the hospitalist later documents septic shock while norepinephrine is infusing after the obstruction has been decompressed, that shock label still has to be the provider’s words, not the drip rate.

Scenario: colon SSI versus HAC programs. On postoperative day 4 after elective colectomy, the wound is opened at the bedside and the surgeon writes that the infection is related to contamination at the anastomosis. Quality staff say this is a HAC. Colon SSI is an NHSN healthcare-associated infection in the HAC Reduction Program if it meets NHSN definitions. It is not automatically one of the fourteen HAC payment-provision SSI categories (those include mediastinitis after bypass grafting, selected orthopedic and bariatric sites, and CIED infection, among others). CDI still needs the causal relationship in the record and honest POA: N if the infection began after the inpatient order. Any query asks about the infection and its timing, not about protecting a HAC score.

Scenario: localized pneumonia, then sepsis. A patient is admitted for community-acquired pneumonia. On hospital day three the attending documents sepsis with acute hypoxemic respiratory failure linked to the infection. Pneumonia occasioned the admission; sepsis developed later. Sequence the localized infection first, then the sepsis and, if linkage is stated, severe sepsis codes. Do not rewrite the principal diagnosis solely because an MCC became available.

Study habits for this cluster

Practice separating clinical definition (Sepsis-3: infection plus SOFA rise of 2 or more) from coding construct (sepsis, severe sepsis R65.2-, septic shock). Practice one nonleading question that never mentions CC, MCC, HAC, or DRG. When organ dysfunction has two plausible causes, query the relationship instead of completing severe sepsis. When a wound infection appears after an operation, look for a provider causal statement, then decide which CMS construct—if any—actually applies, without merging the payment provision with the Reduction Program.