How serious are the symptoms of callers to a telephone triage call centre? 
Adverse events such as deaths following telephone triage calls are rare, suggesting that the process is basically safe.  However, if calls tend to concern mostly minor illnesses, then adverse events following calls would be uncommon even if the triage process itself was flawed.  We investigated hospitalization rates following triage calls and compared them to hospitalization following two other types of medical access, emergency department (ED) visits and office visits.  For the Ask Mayo Clinic telephone triage centre, hospitalization rates for adult calls concerning chest pain and abdominal pain were each 13%.  Based on national survey data, hospitalization for adult ED visits concerning the same symptoms were 33% (chest pain) and 19% (abdominal pain).  Office visits had hospitalization rates significantly lower than triage calls in all age groups, while ED visits had higher hospitalization rates than triage calls in all age groups.  There are both qualitative and quantitative similarities between triage calls and ED visits and, using hospitalization as an indicator, some subgroups of triage calls are nearly as serious as ED visits.