Table 3.
| Infection window period (IWP) | Defined as the 7 d during which all site-specific infection criteria must be met. It includes the collection date of the first positive diagnostic test that is used as an element to meet the site-specific infection criterion, the 3 calendar days before and the 3 calendar days after |
| Date of event (DOA) | Date the first element used to meet an NHSN site-specific infection criterion occurs for the first time within the 7-d infection window period |
| Present on admission (POA) | If the date of event of the NHSN site-specific infection criterion occurs during the POA time period, which is defined as the day of admission to an inpatient location (calendar day 1), the 2 d before admission, and the calendar day after admission |
| Health care–associated infection (HAI) | Localized or systemic condition secondary to infection that was not present at the time of admission to the health care facility |
| Repeat infection time frame (RIIT) | Is a 14-d timeframe during which no new infections of the same type are reported |
| Secondary BSI attribution period | Is the period in which a blood specimen must be collected for a secondary bloodstream infection to be attributed to a primary site infection. This period includes the infection window period combined with the repeat infection timeframe (RIT). It is 14–17 d in length depending upon the date of event. |
| Pediatric VAEs (ventilator-associated events) (PedVAEs) | Patient has a baseline stability or improvement on ventilator, defined by ≥ 2 calendar days or decreasing daily minimum FiO2 ≥ 0.25 or MAP values ≥ 4 cm of H2O sustained for ≥ 2 d. The baseline period is defined as the 2 calendar days immediately preceding the first day of increased daily minimum MAP or FiO2 that is maintained for > 1 h |
NHSN National Healthcare Safety Network