Few medical blunders are due to negligence, officials have claimed. In a paper to legislators, the Health and Welfare Bureau admitted human error was one of the eight possible reasons for medical incidents. But it maintained that only a minor number of cases were due to negligence. The bureau said the 'natural course of medical illness' might be misconstrued by patients as being a medical blunder. Miscommunication between patients' relatives and medical staff and grief arising from loss of life must also be considered. The bureau stopped short of attacking the Hong Kong Sanatorium and Hospital in Happy Valley over dialysis machine blunders which led to three deaths last month, but warned that any substandard hospitals could be denied registration.