An ICU recorded 4 episodes of catheter-associated urinary tract infection during a month in which there were 900 urinary catheter-days and 1200 patient-days. Using the standard NHSN method, which denominator yields the device-associated infection rate expressed per 1000 device-days?
- A Urinary catheter-days ✓
- B Number of admissions during the month
- C Total patient-days
- D Number of catheters inserted
Correct answer: A. Urinary catheter-days
Explanation
Device-associated infection rates are calculated as the number of infections divided by the number of specific device-days, multiplied by 1000, here giving 4 divided by 900 times 1000, about 4.4 per 1000 catheter-days. Using total patient-days (option C) produces a crude rate that mixes exposed and unexposed patients and destroys comparability between units with different catheter utilisation. Device-day denominators allow fair benchmarking across ICUs.
Reference: CDC National Healthcare Safety Network Patient Safety Component Manual, 2024 ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.