Catheter Days Risk Calculator

Work out catheter days risk instantly with clear inputs, formula shown and shareable results.

About Catheter Days Risk Calculator

Compounds the daily risk of catheter-associated bacteriuria across the days in situ, which is why catheter duration is the dominant modifiable risk factor.

Formula

Cumulative risk

Cumulative risk = 1 - (1 - daily risk)^catheter days; the commonly quoted daily bacteriuria rate is 3 to 7%

Worked example

With the default values below, Catheter Days Risk Calculator returns Cumulative bacteriuria risk of 26.49%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Days the catheter has been in placeaccepts 0–60: 6
Daily bacteriuria riskaccepts 0.5–20: 5

Results

Cumulative bacteriuria risk: 26.49%
Assumed daily risk: 5.00%
Risk if left for 30 days: 78.54%
Prompt: Review the indication daily; most catheters can be removed sooner than they are

Step by step

1Values used
2Cumulative risk
3Cumulative bacteriuria risk= 26.49
4Assumed daily risk= 5.00
5Risk if left for 30 days= 78.54
6Prompt= Review the indication daily; most catheters can be removed sooner than they are

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

Frequently Asked Questions

Why does duration matter more than technique?

Bacteriuria accumulates at a few percent per day, so almost all catheters become colonised within a month.

What reduces infection most?

Avoiding insertion and removing the catheter as soon as it is no longer needed.