Where do out-of-hours calls to a consultant microbiologist come from?

There is little in the literature about out-of-hours calls to medical microbiologists. The calls taken by a consultant medical microbiologist over a five-year period in an Irish tertiary referral hospital were reviewed. Excluding calls on weekend mornings and significant evening positive blood cultures, the mean annual number of calls on a one-in-four rota was 89 (range 70-111). Over 90% of calls were received before midnight and 51% were from specialist registrars. Medical specialties, neurosurgery and intensive care were the most common departments seeking advice. Two-thirds of calls related to the management of an individual patient, but advice on infection prevention and control is increasingly requested. Calls out-of-hours are not insignificant but little is known about how these vary between hospitals and what contribution they make to patient care.