An upgrade in a lab services computer program at the regional health care provider in Calgary, Alberta, caused test results to be listed under the wrong patients' names, according to the Calgary Health Region.

Calgary lab services delivers 400,000 lab reports every month, and Calgary Health said that about 2,000 lab tests accessed through the provincial electronic health record system between May 1 and July 5 contained erroneous information. Calgary Health said results delivered directly to physicians and hospitals were not affected by the error.

Calgary Health said that after discovering the error, it shut down its Lab Test Results History system July 6, and it will remain down until further notice. Almost 400 health care providers have accessed incorrect information since May 1, Calgary Health said. As of yesterday, it had notified two-thirds of them about the system problems.

A Calgary Health spokesman could not immediately identify vendors of the systems that caused the error. Last month, Orion Systems International won a contract to provide a provincewide system in Alberta.