HAI Surveillance Summary
HAI Surveillance Summary
The CDC's National Healthcare Safety Network (NHSN) is the primary reporting system for healthcare-associated infections in the United States. Most acute-care hospitals are required to report a defined set of events under CMS Conditions of Participation.
Required event types (acute care)
| Event | Where | Reporting |
|---|---|---|
| CLABSI — central-line-associated bloodstream infection | All ICUs and select wards | Per patient, monthly |
| CAUTI — catheter-associated urinary tract infection | All ICUs and select wards | Per patient, monthly |
| SSI — surgical site infection | Selected NHSN-defined operative procedures | Per procedure, monthly |
| MRSA bacteremia — facility-wide LabID event | Facility-wide | Monthly |
| C. difficile — facility-wide LabID event | Facility-wide | Monthly |
| VAE — ventilator-associated event | Adult ICUs | Per ventilator-day, monthly |
| COVID-19 — HCP and patient cases | All wards | Weekly |
Definitions and timing
- Healthcare-onset (HO): positive specimen collected on day 4 or later of admission (admission day = day 1).
- Community-onset (CO): collected on day 1, 2, or 3 — generally not attributed to the facility.
- Recurrence interval: 14 days (most events) — a new positive specimen within 14 days of a prior event for the same organism does not count as a new event.
Numerator (cases) and denominator (device-days or patient-days)
Surveillance metrics are expressed per 1,000 device-days (CLABSI/CAUTI/VAE) or per 10,000 patient-days (LabID events). Denominators must be collected by the same trained staff using the NHSN protocol.
Standardized Infection Ratio (SIR)
SIR = observed events / predicted events. CMS publicly reports SIRs. Targets are set by HHS HAI Action Plan goals; facilities exceeding the upper 95% CI threshold may face quality scrutiny.
Outbreak threshold
Two or more cases of the same organism in the same unit within a defined timeframe (typically 1 week for acute pathogens, longer for chronic carriers) should trigger an outbreak investigation per facility policy.
Reporting cadence
- Monthly: all NHSN events submitted by the 15th of the following month.
- Annually: facility survey, CMS reporting attestation.
- Real-time: notify state/local public health for reportable conditions per state list (typically within 24 hours for severe events).
Tools
- NHSN web application: https://www.cdc.gov/nhsn/sums/index.html
- Local IPC tracker (this platform's
casesandoutbreakstables) feeds the NHSN submission.