Misdiagnosis may account for many ICU deaths in U.S. hospitals. A report in the November issue of BMJ Quality and Safety reviewed 31 studies containing autopsy information from ICU patients and estimated the annual number of such deaths in the United States to be between 22,600 and 40,500. That number is comparable to those from breast cancer and central line bloodstream infections. In 8% of cases, Class I diagnostic errors (indicating a misdiagnosis that may have led to death) were made. Of the Class I errors, vascular events (41%) and infections (41%) were the most common missed diagnoses. Pulmonary embolisms, heart attacks, pneumonia, and aspergillosis accounted for more than a third of all Class I misdiagnoses. The authors suggest that "diagnostic errors are a significant cause of preventable harm in hospitalized patients," yet "they receive little attention and research."