The provincial health authority says in a release that the breach by an administrative employee occurred at the Richmond Road Diagnostic and Treatment Centre between February and July of this year.
It says it was first alerted to the problem through an audit supplied by Alberta Health.
A review of the audit confirmed multiple accesses to diagnostic, treatment and care data.
AHS says patient care and the accuracy of patient records were not affected.
It also says the worker is no longer employed by the organization and the matter has been reported to Alberta Health and the province's information and privacy commissioner.
The authority said it will work with the commissioner in any potential investigation.
The breaches occurred in Alberta Netcare — the provincial electronic health record system — and AHS's Calgary Zone Clinibase system.
Clinibase manages everything from referrals and waitlists to the admission, transferring and discharging of patients.
“This privacy breach is unacceptable and disappointing,” AHS vice-president Todd Gilchrist said in the statement Friday.
“We will be further enhancing our efforts to reinforce the importance of appropriate access and safeguarding patient information.”