DETROIT (WWJ) – Roughly 18,500 patients at Henry Ford Health System have possibly had their personal information stolen in a data breach.

Officials say the breach was discovered in early October after the email credentials of a group of employees were stolen, which gave the thief access to patients’ records.

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Personal information viewed or stolen may have included a patient’s name, date of birth, medical record number, provider’s name, date of service, department’s name, location, medical condition and health insurer. Neither Social Security numbers nor credit card information were revealed.

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“We are very sorry this happened,” Henry Ford Health System said in a statement. “We take very seriously any misuse of patient information, and we are continuing our own internal investigation to determine how this happened and to ensure no other patients are impacted.”

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Patients who feel their information was compromised can request new medical record numbers to protect themselves. Patients who received a notification letter are asked to call 844-327-2396.