Nason Medical Center on Rivers Avenue in North Charleston is no longer open on weekends, but a spokeswoman for the company did not confirm if the new summer hours have anything to do with staffing shortages or an ongoing government investigation.

"These hours have been adopted because weekend patient volume always declines this time of year at that location," said Cheryl Smithem, who manages the urgent care network's public relations.

Four other Nason Medical Centers remain open every day from 8 a.m. to 8 p.m.

The center on Rivers Avenue, which opened in 2010, treats a large percentage of low-income Medicaid patients, Dr. Barron Nason said in an interview earlier this year. Doctors and hospitals make less money treating Medicaid patients because the reimbursement is generally lower than payments from Medicare or private insurance companies.

Nason did not return messages to discuss the new hours on Tuesday.

The company told The Post and Courier in May that the government ordered all five centers to discontinue CT scans and ultrasounds. Nason Medical Center's imaging specialists were fired that month, Smithem confirmed at the time. Several doctors and physician assistants have since voluntarily left the practice.

Government officials have declined to comment on the case and the company will not explain why it is being investigated.

A court case, which was sealed from the public earlier this summer, revealed that one of the company's owners said Nason Medical Center's parent company is unable to pay outstanding bills in excess of $1.2 million and that its CEO manipulated accounts to inflate profitability on paper.

BlueCross BlueShield of South Carolina announced in June it would cut Nason Medical Center from most of its insurance plans later this year, although the insurer announced Friday it reached an agreement that will keep the urgent care centers in the network.

Reach Lauren Sausser at 937-5598.