Letter to the editor

Abstract

Harrington et al's establishment of a rate of intravascular device-related bacteraemia (IVDRB) in an ICU [see 'Intravascular device-related primary bacteraemia rates in a general intensive care unit AIC 4(3):8-11] using recognised standardised definitions and methodology is to be commended. The rate was established from a 6-month period of surveillance. When such a rate is estimated using a proportion of in-patients rather than all patients during an entire year, it is helpful to readers to present the probability of the accuracy of that rate. Harrington et al's rate is a point estimate and the measure of accuracy of this estimate is called the confidence interval. The most commonly used interval is the 95 per cent confidence interval, with the ends of this interval known as the confidence limits.