Blood Culture Guidelines for Adults

Blood Volume Requirements

• The volume of blood collected is the most important variable in recovering bacteria and fungi from patients with bloodstream infections 3, 4
• For adults, 20-30 mL of blood per culture set is recommended, depending on the manufacturer of the instrument 1, 2
• This total volume should be distributed into at least 2 blood culture bottles, with each bottle typically containing 8-10 mL of blood 1, 5
• Most manufacturers' bottles accept a maximum of 10 mL per bottle 6

Recommended Blood Culture Protocol

• Obtain 2-4 blood culture sets per septic episode in adults 1, 2
• Each set should consist of 20-30 mL of blood distributed into at least 2 bottles 3, 4
• Typically, blood specimens are split between aerobic and anaerobic blood culture bottles 6
• In some circumstances (e.g., when fungemia due to yeast is suspected), it may be prudent to split blood specimens between 2 aerobic vials instead 6

Special Considerations

• For specific organisms like Bartonella spp. or Legionella spp., specialized collection methods such as lysis-centrifugation tubes may be required, with 10 mL of blood inoculated directly into each tube 1, 5
• For yeast detection, 20-30 mL of blood per culture set is still recommended, but distribution may favor aerobic conditions 1, 7