Agreement of unique isolation/detection specimens depending on the gold standard used and the specimen type.

A) Blood culture gold standard: 96.7% sensitivity, 97.71% specificity, 95.2% PPV, 98.5% NPV. Clinical infection criterion: 96.8% sensitivity, 98.5% specificity, 96.8% PPV, 98.5% NPV.aIn one specimen an Enterococcus faecium was isolated by blood culture whereas PCR/ESI-MS detected a coagulase-negative staphylococci.bIn another specimen a Klebsiella pneumoniae was isolated by blood culture and it was identified as Citrobacter spp. by PCR/ESI-MS.B) Blood culture gold standard: 43.8% sensitivity, 88.4% specificity, 58.3% PPV, 80.9% NPV. Clinical infection criterion: 50.0% sensitivity, 93.8% specificity, 78.7% PPV, 80.4% NPV.cThe PCR/ESI-MS detected a coagulase-negative staphylococci while a Klebsiella pneumoniae was isolated by blood culture. In 10 specimens with a negative paired blood culture (two of them from the same patient and sepsis episode) the PCR/ESI-MS detected clinically significant microorganisms.