There are apparently 12 million patients misdiagnosed every year in outpatient clinics.

About 12 million adults in the United States are misdiagnosed annually. More than half of these errors are potentially harmful. This is according to a new study in the British Medical Journal Quality and Safety.

Patient safety begins with healthcare providers making a correct and timely diagnosis - considering all the available information, such as family history, symptoms, clinical exam results, diagnostic test results, lab values, etc. The researches in this study reviewed three studies that went through medical records using electronic triggers to detect unexpected return visits. These unexpected return visits were an indicator of an incorrect diagnosis or lack of follow-up when there were abnormal findings. They also found errors had occurred when there was adequate information during the first clinic visit to correctly diagnose the condition or to document abnormalities in which tests would have revealed a condition.

Through this study they found that delayed cancer diagnosis was one of the most harmful and most expensive types of diagnostic errors in the outpatient setting. The study reviewed 81,483 patients in two health systems who visited the clinic 212,165 times in one year. What they found was that 1,100 patients were admitted to the hospital within 14 days of visiting the clinic. Out of the 1,100 visits, 674 sample visits showed 1,141 errors.

There are a lot of reasons for these figures - doctors are rushed, clinics don't have systems for following up on test results.  Those are things outpatient clinics, hospitals, HMOs and doctors' offices can change.

For more information of this report, go to For the orginal report, go to