Diagnosis of venous access port-related infections

The accumulation of infected clots under the silicone septum of the reservo ir of venous access ports (VAPs) has been reported. We analyzed the relatio nship between these deposits and the occurrence of VAP-related bloodstream infections (VAP-BSIs) by (1) evaluating the accuracy of paired quantitative blood cultures for diagnosing VAP-BSI before the removal of the device and (2) assessing the accuracy of cultures of the tip and septum (i.e,, the in ternal lumen of the VAP) for diagnosing VAP-BSI after removal of the device . Over a 16-month period, all VAPs removed were prospectively investigated. Before VAP removal, paired quantitative blood cultures were 77% sensitive and 100% specific and had a positive predictive value of 100% and a negativ e predictive value of 98% for diagnosing VAP-BSI. After VAP removal, tip cu lture was only 46% sensitive, whereas septum culture was 93.3% sensitive fo r confirming the diagnosis of VAP-BSI. Thus infected deposits that accumula te under the VAP septum are the source of VAP-BSI.