Objective: Use of the bacteriology laboratory to guide antibiotic prescribing in primary care is often considered inappropriate due to difficulties of access in a relevant time scale. The overnight analysis offered to general practitioners in the Grampian area of Scotland for the past 6 years (ABLE), and which had previously been shown to reduce antibiotic prescribing by two-thirds in a randomized controlled trial, was audited to see if it was being used correctly in general practice, that is to reduce unnecessary antibiotic prescribing. Methods: 699 consultations were audited. Of these, 357 were ABLE patients. The other 342 were chosen because an antibiotic had been prescribed. Results: Only 36.7% (140) of the ABLE patients were prescribed an antibiotic, 65.7% being given a delayed action script. All but 10 were culture positive. ABLE patients had a greater proportion of urinary tract infections than the non-ABLE patients, but less lower-respiratory and skin or soft-tissue infection. The antibiotics prescribed reflected the differences in infection type. The repeat visit rate and repeat antibiotic prescription rate were almost identical between the two groups.Conclusion: While the overall use of ABLE in Grampian is low, its use seems to be appropriate in that it is successfully being used to identify bacterial infection and reduce unnecessary antibiotic prescribing.