All patients were observed for clinical signs of local infection at the PNC insertion site and for clinical signs of systemic infection one week after PNC-removal. For the correlation of the detection of bacteria on the PNC with clinical signs of in-flammation, the sensitivity, specificity, positive and negative predictive values were calculated on the basis of the following three categories: 1) any growth of bacteria including enrichment, 2) more or equal 5 colonies and 3) more or equal 15 colonies with the semiquantative culture technique, respectively.