Cigna violated the law by denying claims for imaging and other healthcare services in bulk, a class action lawsuit filed on Monday alleges.

The Bloomfield, Connecticut-headquartered health insurer utilizes an algorithm called PXDX, purportedly enabling its staff medical doctors to automatically reject payment requests in “batches of hundreds of thousands at a time” based on pre-set criteria. This, the complaint alleges, allowed Cigna to evade California’s legally required individual physician review process.

“Relying on the PXDX system, Cigna’s doctors instantly reject claims on medical grounds without ever opening patient files, leaving thousands of patients effectively without coverage and with unexpected bills,” attorneys with Clarkson Law Firm in Malibu, California, alleged in the complaint. “The scope of this problem is massive. For example, over a period of two months in 2022, Cigna doctors denied over 300,000 requests for payments using this method, spending an average of just 1.2 seconds ‘reviewing’ each request.”

Plaintiff attorneys filed the complaint July 24 in California District Court on behalf of state residents Suzanne Kisting-Leung, Ayesha Smiley and others in similar situations. In one alleged instance, Kisting-Leung underwent a transvaginal ultrasound following a referral from her doctor, who suspected possible ovarian cancer. The results revealed a dermoid cyst on her left ovary. However, on or around Oct. 17, she received a letter from the radiology department informing her that Cigna had allegedly denied the claim, stating that it was not medically necessary.

Attorneys said she owed $198 out of pocket for the exam, and she was referred for another in November 2022, again receiving a denial and bill from her provider totaling $525 for the second ultrasound.

“Ms. Kisting-Leung vigorously appealed Cigna’s decision to deny coverage,” the complaint alleged. “To date, Cigna has not paid Ms. Kisting-Leung’s claim.”

The health insurer, one of the country’s largest with some 2.1 million beneficiaries in California alone, did not immediately respond to a Radiology Business request for comment late Monday. Nonprofit news organization ProPublica previously chronicled Cigna’s use of its claims-denial algorithm in March, alleging that one medical director at the health plan denied 60,000 claims in a single month last year.

At the time, Cigna said the system was designed to “accelerate payment of claims for certain routine screenings. This allows us to automatically approve claims when they are submitted with correct diagnosis codes,” the company told ProPublica.

“PXDX is a simple tool to accelerate physician payments that has been grossly mischaracterized in the press,” spokeswoman Justine Sessions said in a statement shared Monday by Forbes. “The facts speak for themselves, and we will continue to set the record straight.”

Clarkson Law Firm is requesting damages in excess of $5 million, not including interest and other costs, and is seeking class-action status for the complaint.

The Department of Justice also filed suit against Cigna in October 2022. U.S. attorneys claimed the insurer submitted false and invalid patient diagnosis codes to artificially inflate payments received for providing insurance coverage to its Medicare Advantage plan members. Cigna said at the time that it would vigorously defend against the allegations.