MedStar Health says 90 percent of its computer systems are back online after it fell victim to a crippling attack that encrypted data this week.
Inpatient and outpatient health records systems were up and running Friday, as were registration and scheduling systems, MedStar said in a statement.
The health system, which operates 10 hospitals and other facilities in the region, said it gave priority in its recovery efforts to fixing computer systems used for patient care and is now turning to resolve other problems.
MedStar reported the problems, which it has described as a computer virus, on Monday. Technical teams pulled systems offline to stop the infection from spreading, the company said, leaving clinicians to rely on paper records to track patients.
The hospital network is the latest high-profile victim of a type of attack known as ransomware, in which hackers demand payment in exchange for keys to regain access to data that they have encrypted.