Blood cultures taken before antibiotics have a much higher yield than those taken after. Two sets from separate sites, with adequate volume, are standard.
In septic shock, antibiotics should not wait for cultures, but in most patients both can be done within minutes.
- Two sets from separate sites, each with adequate blood volume, improve yield.
- Do not delay antibiotics in septic shock to obtain cultures.
- Label the time and site of each sample.
- Review cultures at 48 to 72 hours to narrow or stop therapy.
Why it matters
A single dose of antibiotic can sterilise cultures, and a missed organism makes de-escalation and duration decisions guesswork.
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