A lawyer is trying to organize a class-action suit that would attack the methods a health insurer is using to estimate “usual, customary and reasonable” fees for out-of-network doctors and hospitals.

Barry Epstein, a Woodbridge, N.J., lawyer, has filed the suit, Cooper et al. vs. Aetna Inc., in the U.S. District Court in Newark, N.J.

Epstein alleges that Aetna Inc., Hartford, violated Employee Retirement Income Security Act by relying on a flawed database administered by a unit of UnitedHealth Group Inc., Minnetonka, Minn., to come up with unrealistically low estimates of usual, customary and reasonable fees for plan members’ care.

In New Jersey, a managed care plan member who receives care out-of-network is responsible for the gap between what providers have billed and what the carrier has paid.

Aetna received the suit Aug. 1 and is reviewing the complaint, the company says.

“Aetna believes this lawsuit is without merit and will defend this action vigorously,” the company says. “Reimbursement of non-participating providers is a complex issue, and Aetna strives to implement policies that are in the best interests of its members and employers who purchase benefits plans.”