Aims As laboratories move towards 24 h a day working patterns, we aim to evaluate if expediting the availability of provisional blood culture results outside of normal working hours would derive clinical benefit.

Methods 116 blood cultures flagging positive outside of conventional working hours (20:00–09:00) were studied. In each case, medical records were reviewed and cases discussed with clinicians to determine if earlier communication of results would have altered management and affected the outcome.

Results Organisms were seen in 102/116 blood cultures. In total, 76/82 (92.7%) patients with cultures deemed to be significant were on an antibiotic. The isolate was sensitive to the prescribed antibiotic in 56/74 (76%) cases. Input from a microbiologist is likely to have altered management in 14 (13.7%) cases, but unlikely to have affected any outcomes.

Conclusions We found no compelling evidence that expediting the availability of Gram stain results from positive blood cultures alone improves patient outcome.