Blood Culture

1. Indications: Evaluation of bacterial infection
   1. Bacteremia
   2. Sepsis
2. Technique
   1. Preparation of skin
      1. Chlorhexidine (preferred agent for antiseptic)
         1. Superior to povidone-iodine
         2. Superior to Alcohol
      2. Povidone-Iodine
         1. Wait to draw blood for 2-3 minutes after applying
         2. High contamination rate compared with Chlorhexidine
      3. References
         1. Mimoz (1999) Ann Intern Med 131:834-7
   2. Standard collection protocol
      1. Collect up to 3-4 sets of Blood Culture bottles
         1. Two Blood Culture bottles in each set
         2. Obtain 5 ml blood per bottle
      2. Draw from up to 3 different venipuncture sites
      3. Space blood collections by 1 hour intervals
   3. New collection protocol: Six bottle method
      1. Collect 6 bottles from one venipuncture (total 40 ml)
      2. Based on mathematical model
      3. Predicts highest sensitivity and Specificity
      4. References
         1. Lamy (2002) Clin Infect Dis 35:842-50
3. Efficacy
   1. Sensitivity
      1. Increases with number of Blood Cultures drawn
      2. With 3 Blood Cultures, Sensitivity approaches 90%
   2. Study of hospitalized patients with persistent fever
      1. Post-antibiotic culture unlikely to yield pathogen
      2. Obtain pre-antibiotic Blood Culture and await results
      3. Grace (2001) Clin Infect Dis 32:1651-5