Excluding medical and haematological conditions as a cause of bruising in suspected non-accidental injury.

A mistaken diagnosis of child abuse can occur in a number of medical conditions, many of which can be readily diagnosed by experienced paediatricians. Bleeding disorders offer a greater challenge, especially when court proceedings may demand their exclusion. Some of these disorders are rare but more prevalent in areas which have a high incidence of consanguinity. We advocate two stages of laboratory investigations but the limitations of some of these tests and their inability to exclude a bleeding disorder with absolute certainty should be recognised. However, if personal and family histories are absent and both first-stage and second-stage investigations are normal, it is highly unlikely that a bleeding disorder will be missed.