More than one out of every three people say they have been in a situation where a medical mistake such as a misdiagnosis was made, according to a Harris Poll survey conducted on behalf of the American Medical Association's National Patient Safety Foundation. The AMA began organizing the NPSF last year following number of widely reported medical blunders.

• Some 42 percent say they or a friend or relative have been involved in a medical mistake situation.

• A total of 40 percent were affected by misdiagnoses or wrong treatment, and 28 percent reported being affected by medication errors.

• Some 22 percent cited mistakes during a medical procedure.

• More than half the respondents in the telephone survey of 1,513 adults blame medical errors on carelessness, improper training and poor communications.

Lucien Leape of the Harvard School of Public Health, an NPSF board member, estimates that as many as three million medical errors occur in hospitals each year, costing up to $200 billion.