The tool that decides whether an infection was caught in hospital

Whether a patient's infection is healthcare-associated (HAI) or **present
on admission (POA)** is one of the more consequential judgements in hospital
surveillance: it determines whether the infection counts against the facility,
and it feeds every national HAI statistic.

The judgement turns on dates and defined windows. The **NHSN Worksheet
Generator** is a web-based tool that applies them, following the guidance in
the Patient Safety Component Manual, Chapter 2.

What it works out

• The 7-day Infection Window Period
• The Date of Event, and the POA or HAI determination
• The 14-day Repeat Infection Timeframe (RIT)
• The Secondary Bloodstream Infection Attribution Period, where applicable

These are the timing rules that stop the same infection being counted twice,
and that separate an infection a patient arrived with from one they acquired.

What it deliberately does not do

**The Worksheet Generator does not determine that all NHSN infection criteria
have been met.** That remains the user's judgement: the tool answers "given
these dates, which window does this fall in", not "is this an infection".

It is also not for SSI surveillance, and not for the ENDO definition.
Separate tools exist for VAE and for MDRO and CDI LabID events.

A calculator that resolved the clinical question as well as the temporal one
would be doing the surveillance definition's job, and would make every
facility's numbers a product of a web form rather than of trained review.

What it does with your data

**It does not ask for patient identifiers. It stores nothing you enter. It
reports nothing — no data and no determination — to NHSN.** You cannot export
from it, though you can print the worksheet.

That is worth stating plainly, because a hospital user's first question about
a CDC web tool is reasonably whether entering a case sends it anywhere. It
does not.

*Source: National Healthcare Safety Network, Centers for Disease Control and
Prevention.*