Predictive value of blood cultures positive for coagulase-negative staphylococci: implications for patient care and health care quality assurance.
Interpretation of blood cultures that are positive for coagulase-negative staphylococci (CoNS) is often difficult. Predictive values for blood cultures positive for CoNS in patients with a central vascular line in place were calculated using the following rates: true bacteremia, 3%; blood culture contamination, 2%; detection of bacteremia, 80%; and catheter colonization, 2% (for blood samples obtained through a central vascular line). Positive predictive values were 55% for 1 positive culture result of 1 culture performed, 20% for 1 positive result of 2 performed, and only 5% for 1 positive result of 3 performed. For 2 positive culture results of 2 cultures performed, the positive predictive value was 98% if both samples were obtained through the vein, 96% if one sample was obtained through a catheter and the other was obtained by vein, and only 50% if both samples were obtained through a catheter. Use of this model with institution-specific values for input parameters would assist in clinical decision-making as well as hospital quality assurance.
Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA, USA. jit1@cdc.gov
Jerome I
JI
Tokars
D016470:Bacteremia / Q000175:diagnosis / Q000382:microbiology*; D001769:Blood / Q000382:microbiology*; D002408:Catheters, Indwelling / Q000382:microbiology; D003030:Coagulase / Q000032:analysis; D004866:Equipment Contamination; D006801:Humans; D015233:Models, Statistical; D011237:Predictive Value of Tests; D013203:Staphylococcal Infections / Q000175:diagnosis* / Q000382:microbiology; D013210:Staphylococcus / Q000145:classification / Q000201:enzymology / Q000302:isolation & purification*
D003030:Coagulase