Trident Health System is closing two neighborhood health centers in North Charleston as part of an effort to cut costs by consolidating services.

Archdale Medical Center off Dorchester Road offers laboratory work, physical therapy, mammography and computed tomography scans. It will close March 12.

The smaller Whitehall Diagnostic Center, which is equipped to handle CT scans, will close Tuesday.

Combined, the two facilities saw about 1,000 patients each year.

Patients who now visit the two centers likely will be directed to Summerville Medical Center, also operated by HCA Inc.-owned Trident, where the company recently installed new equipment.

"We added a new CT scanner, new digital mammography equipment and also enlarged our physical therapy department," Michael Herman, the hospital's vice president of operations, said in an e-mail. "These improvements and our need to reduce our spending led to our decision."

The consolidation plan will affect five employees — four medical technicians and an administrative worker — who might be able to transfer to other Trident facilities, said spokeswoman Julie Plummer.

The company has not determined how much savings it will see from the closings, she said.

Lynn Bailey, a Columbia-based health care consultant, said smaller medical centers are less profitable to operate because they are reimbursed less than what full-service hospitals receive from Medicare and other health insurers.

"Medicare believes and has always believed that services provided by a physician's office or an outpatient center are less costly to deliver than a hospital," she said. "They're not open 24/7."

Bailey estimates that hospitals get more than twice the reimbursement payments for the same services provided at a freestanding clinic.

Still, some hospitals continue to operate separate medical centers as a community service.

"This was a convenience," Bailey said of Trident's North Charleston health-care outposts. "It was a way of showing the brand, showing the flag and then funneling patients into the HCA network system."