The American Medical Association and other medical societies are suing another health insurer over allegations that the insurer has used illegal means to hold down rates paid to out-of-network doctors.

The plaintiffs filed the suit, against WellPoint Inc., Indianapolis, in the U.S. District Court in Los Angeles.

The plaintiffs are seeking court permission to represent a class of physicians affected by the WellPoint system for estimating typical rates for medical care.

WellPoint uses the estimates to determine how much it will pay for care provided by physicians outside its provider network.

In addition to the AMA, Chicago, the plaintiffs include the California Medical Association, Sacramento, Calif.; the Connecticut State Medical Society, New Haven, Conn.; the Medical Association of Georgia, Atlanta; and the North Carolina Medical Society, Raleigh, N.C.

The AMA helped file similar suits against Aetna Inc., Hartford, and CIGNA Corp., Philadelphia, in February.

In the suits, the plaintiffs say insurers conspired with the Ingenix health pricing database unit of UnitedHealth Group Inc., Minnetonka, Minn., to depress reimbursement rates.

“WellPoint is committed to providing appropriate reimbursement for out of network services,” a WellPoint representative says in a response to the suit. “We are in the process of reviewing the complaint and are unable to comment further at this time.”