(Reuters) - UnitedHealth's unit Change Healthcare said on Friday it has enabled a new instance of its service for all its customers, days after it reported a hack that had a knock-on effect on players across the U.S. healthcare system.

"We have completed standing up a new instance of Change Healthcare's Rx ePrescribing service," the company said in an update on its status page.

Change, which provides healthcare billing and data systems, added that it has completed testing with vendors and multiple retail pharmacy partners for transaction types that were impacted.

Pharmacies across the United States have been experiencing disruptions following the cyberattack at the tech unit, which was perpetrated by hackers who identified themselves as the "Blackcat" ransomware group.

The hack, disclosed last Wednesday, led to disruptions triggered by the attack which have impacted electronic pharmacy refills and insurance transactions.

(Reporting by Sriparna Roy in Bengaluru; Editing by Shailesh Kuber)