TABLE 1.

Major National Healthcare Safety Network (NHSN) Modifications in Healthcare-Associated Infection (HAI) Definitions, 2013 and 2014

HAI	NHSN terminology change	Criteria and/or criteria modifications	Justification for changes	Timing
VAP	VAE, divided into 3 tiers: VAC IVAC Possible and probable VAP	Under new definition algorithm, patient is identified as having VAE when mechanical ventilation is received for >2 calendar days with a combination of: Deterioration in respiratory status after a period of stability or improvement on the ventilator Evidence of infection or inflammation Laboratory evidence of respiratory infection Criteria apply to: Adult inpatient locations For VAC: interfacility comparisons, given uncertainties that exist in defining lung injury as definitively infectious	Reduces: Variability in case-finding11,64 Time spent conducting surveillance Improves: Definition objectivity Reliability Includes potentially automatable component.	2013
CLABSI	MBI-LCBI	Under new definition, patient is identified as having MBI-LCBI (a primary BSI) when meeting criteria for: Presence of selected organisms (viridans group streptococci, Enterobacteriaceae, Candida species, certain anaerobes) AND neutropenia: ANC <500 for multiple days OR A single ANC <100 OR Allogeneic hematopoietic stem cell transplant: Documented grade 3–4 gastrointestinal graft-versus-host disease OR Severe diarrhea	Minimizes misclassification when GI source is likely65 Targets prevention efforts based on likely route of infection Demonstrates high agreement between reporter and CDC classification of MBI-LCBI (91%, k=.82)1	January 2013
SSI	None	Modifications to NHSN operative procedure definition: “Primarily closed incisions” include those with wire drains or wire extruding the incision Reporting of all SSI types for all NHSN procedures limited to 30 days after the date of the procedure EXCEPT deep incisional and organ/space SSI, which are reported up to 90 days after the procedure	Improves reliability of risk-adjusted SSI metrics through application of procedure-specific, multivariate risk models that incorporate additional weighted patient factors10 Increases consistency across institutions Accounts for variability in patient case mix Provides basis in consistent case detection systems Reduces data collection burden
CAUTI	None	Modifications to NHSN definition: A UTI is considered a catheter associated HAI if the device was in place for >2 calendar days, with day of device placement being day 1, and catheter was in place when all elements of the UTI criterion were first present together. UTIs occurring on the day of device discontinuation or the following calendar day are considered device associated HAIs if the device had been in place already for >2 calendar days.	More reliably excludes infection that is not healthcare-associated By instituting a minimum period that the catheter must be in place, the new definition is more physiologically aligned with pathogenesis of device-associated HAI	2013

NOTE. ANC, absolute neutrophil count; CAUTI, catheter-associated urinary tract infection; CLABSI, central-line associated bloodstream infection; HAI, healthcare-associated infection; IVAC, infection-related ventilator-associated complication; MBI-LCBI, mucosal barrier injury–laboratory-confirmed bloodstream infection; NHSN, National Health and Safety Network; SSI, surgical site infection; UTI, urinary tract infection; VAC, ventilator-associated condition; VAE, ventilator-associated event; VAP, ventilator-associated pneumonia.