RALEIGH — North Carolina advocates for patients with developmental disabilities say more than 600 children and adults are losing critical Medicaid services because of how a managed care provider in the Southern Piedmont is calculating levels of need.

Disability Rights North Carolina said Tuesday it and other groups filed a federal class action lawsuit for Medicaid consumers against Piedmont Behavioral Health Care and N.C. Health and Human Services Secretary Lanier Cansler.

Piedmont Behavioral covers Rowan, Davidson, Stanly, Cabarrus and Union counties.

The lawsuit contends Piedmont Behavioral used hard-to-understand rules to reduce or eliminate services July 1 without giving patients a chance to challenge decisions. The advocates want services restored until changes are made.

A spokeswoman for Cansler said the department must be focused on appropriate levels of care when money is tight.