CAUTI: NHSN Surveillance Definition, SUTI Criteria, and Reporting

CAUTI (catheter-associated urinary tract infection) is a National Healthcare Safety Network (NHSN) surveillance category, not a clinical diagnosis of “the patient has a UTI.” NHSN defines it through a structured algorithm: an indwelling urinary catheter must have been in place for a specific duration relative to the date of event, and the case must independently meet one of NHSN’s Symptomatic Urinary Tract Infection (SUTI) or Asymptomatic Bacteremic UTI (ABUTI) criteria, each built from a specific combination of signs/symptoms and quantitative urine culture results. This guide works through that adjudication using the criteria published in the CDC NHSN Patient Safety Component Manual, Device-associated Module, Chapter 7 (Urinary Tract Infection Events), January 2024 edition, the most recent edition available for direct verification. NHSN revises this manual annually, typically each January; confirm the current-year manual before using any of this for official reporting.

Surveillance CAUTI Is Not the Same as “This Catheterized Patient Has a UTI”

This is the distinction that matters most operationally, because CAUTI rates feed CMS Hospital-Acquired Condition (HAC) Reduction Program penalties and public reporting: a catheterized patient with bacteriuria and no symptoms does not have a reportable CAUTI, and a catheterized patient treated empirically for a “UTI” without a qualifying urine culture and symptom combination may not meet the surveillance definition either. NHSN’s own definition explicitly excludes several common bedside symptoms — urgency, frequency, and dysuria — from counting toward CAUTI while the catheter is actually in place, on the reasoning that an indwelling catheter itself commonly causes those complaints. An infection preventionist adjudicating a case is applying the NHSN algorithm as written, not simply confirming a treating clinician’s UTI diagnosis.

Step 1: Is There an Indwelling Urinary Catheter (IUC), and for How Long?

NHSN defines an indwelling urinary catheter as a drainage tube inserted into the bladder through the urethra, left in place, and connected to a drainage bag (including leg bags) — commonly called a Foley catheter. IUCs used for intermittent or continuous irrigation are included. Explicitly excluded: condom catheters, straight in-and-out (intermittent) catheterization, and nephrostomy tubes, ileoconduits, or suprapubic catheters unless an actual IUC is also present.

A UTI becomes catheter-associated when the IUC has been in place for more than two consecutive calendar days in an inpatient location (day of placement is Day 1), and the catheter was either present for any portion of the date of event or was removed the day before the date of event. If a catheter is removed after meeting the >2-day threshold, the UTI’s date of event must fall on the day of discontinuation or the next day for the case to still count as catheter-associated. NHSN also has explicit rules for interrupted catheterization: if a patient goes at least one full calendar day without any IUC after a removal, the device-day count restarts; if a new catheter is placed before a full day passes, the count continues uninterrupted. This is the same >2-day device-eligibility logic used across NHSN’s device-associated modules (compare the central-line-day rule for CLABSI).

Step 2: Does the Case Meet a UTI Criterion?

NHSN’s Table 1 defines three criteria, and which one applies depends on catheter status and patient age:

• SUTI 1a (Catheter-Associated) — Requires all three: (1) an IUC in place for more than two consecutive days, present on the date of event or removed the day before; (2) at least one of fever (>38.0°C), suprapubic tenderness, or costovertebral angle pain/tenderness (urinary urgency, frequency, and dysuria cannot be used while the catheter is in place); and (3) a urine culture with no more than two species of organisms, at least one of which is a bacterium at ≥10&sup5; CFU/mL. All elements must fall within the infection window period (IWP).
• SUTI 1b (Non-Catheter-Associated) — The same symptom and culture structure as 1a, but for a patient who either never had a qualifying IUC or whose IUC had not yet been in place for more than two days on the date of event; here urgency, frequency, and dysuria are usable symptoms since no catheter is confounding them.
• SUTI 2 (patients ≤1 year of age, with or without a catheter) — Uses an infant-specific symptom list (fever, hypothermia, apnea, bradycardia, lethargy, vomiting, suprapubic tenderness) plus the same ≥10&sup5; CFU/mL culture requirement; whether the case is classified as CAUTI or non-catheter-associated UTI depends on whether a qualifying IUC was in place.

Fever cannot be excluded from a UTI determination just because it is clinically attributed to another cause — NHSN treats fever as inherently non-specific and requires it be counted regardless. A small number of organisms are categorically excluded from meeting the UTI culture requirement: Candida species and unspecified “yeast,” mold, dimorphic fungi, and parasites (an acceptable specimen may still include these if a qualifying bacterium at >100,000 CFU/mL is also present). “Mixed flora” is not a usable organism for meeting NHSN’s UTI criteria at all.

UTI is always treated as a primary site of infection under NHSN’s rules — unlike a bloodstream infection, it is never itself classified as secondary to another site.

ABUTI: The Asymptomatic Bacteremic Pathway

Beyond the symptomatic SUTI criteria, NHSN also recognizes Asymptomatic Bacteremic UTI (ABUTI) for patients without the qualifying urinary signs/symptoms who instead have a matching organism identified in both a urine culture meeting the quantitative threshold and a blood culture, without evidence the bacteremia is secondary to infection at another site. Both SUTI- and ABUTI-classified cases, when catheter-associated, count toward CAUTI reporting requirements under applicable CMS and state programs.

Putting It Together: What “CAUTI” Means as a Count

A case is a reportable CAUTI when: a qualifying IUC was in place for more than two consecutive days relative to the date of event, and the case independently meets a SUTI (1a or 2, catheter-associated) or ABUTI criterion. Facilities track catheter-days as the denominator and CAUTI counts as the numerator, then compare observed CAUTIs to a risk-adjusted predicted number using the Standardized Infection Ratio (SIR) — see that entry for how the predicted count, confidence interval, and small-denominator instability actually work.

Frequently Asked Questions

Does a catheterized patient with bacteria in the urine but no symptoms have a CAUTI?

No. Asymptomatic bacteriuria alone does not meet NHSN’s SUTI criteria; a qualifying sign or symptom is required (unless the ABUTI pathway applies, which requires a matching bloodstream organism instead).

Can urinary urgency or dysuria be used to diagnose a CAUTI?

Not while the catheter is in place. NHSN excludes urgency, frequency, and dysuria as qualifying symptoms for SUTI 1a specifically because an indwelling catheter itself commonly causes those complaints; they can be used for SUTI 1b, which by definition involves a patient without a currently-qualifying catheter.

How long does a urinary catheter need to be in place before a UTI can count as a CAUTI?

More than two consecutive calendar days, with the catheter present on the date of event or removed the day before — the same >2-day structure NHSN uses for central lines in CLABSI surveillance.

What urine culture result is required?

No more than two species of organisms identified, with at least one bacterium present at ≥100,000 (10&sup5;) CFU/mL, within the infection window period.

Who applies the CAUTI definition in a hospital?

Typically an infection preventionist, reviewing the chart against the NHSN algorithm rather than relying on the treating clinician’s documented diagnosis.

This guide summarizes the structure of the NHSN Chapter 7 (UTI/CAUTI) surveillance criteria as published in the January 2024 Patient Safety Component Manual for general orientation. It is not a substitute for the current-year NHSN manual and is not clinical guidance for individual patient management. For official reporting, always work from the exact current-year CDC NHSN manual chapter and any program-specific reporting instructions (e.g., CMS HAC Reduction Program).

Related: see the Patient Safety & Infection Prevention hub and the CLABSI guide for the equivalent device-day and laboratory-confirmed infection logic applied to central lines.