When AI Breaks

Cigna doctors denied over 300,000 claims in two months without opening the files

Its PxDx software flagged claims whose procedure did not match an approved diagnosis, and medical directors signed the denials in batches at about 1.2 seconds each.

7 min read2026-09-09

Why this matters

Every health insurer runs software that decides, on the first pass, whether to pay a claim. Most of the time you never see it work. Cigna's version, called PxDx, became visible in 2023, when reporters obtained the company's own records and found its doctors denying hundreds of thousands of claims at a rate of about a second each. This lesson explains what PxDx actually is, what it did over two months of 2022, and why a required human review that has shrunk to a signature produces wrong denials at scale. By the end you will be able to say why the speed of a decision can itself be the proof that no real review happened. You will also recognize the same arrangement in the prior-authorization and claims systems that decide what your own care costs.

Background optional reading

01: Michigan spent nearly two years accusing jobless workers of unemployment fraud with no human examiner: the same failure with no human in the loop at all.

A list matches the procedure to the diagnosis

PxDx is short for procedure-to-diagnosis, and it is a list. When a provider bills Cigna for a procedure, software compares the billed procedure code against the diagnosis code on the same claim. The list records which diagnoses Cigna accepts as reasons to perform each procedure. If the diagnosis sits on the accepted list, the claim moves toward payment. If it does not, the software flags the claim so a Cigna doctor can deny it.¹

The requirement PxDx sits inside is old and specific. California insurance regulation requires an insurer to give each bill a "thorough, fair, and objective" investigation before it refuses to pay.² In practice that means a qualified medical director examines the patient's records, reads the coverage policy, and decides the case on its own facts. PxDx does not remove that step on paper. A Cigna medical director still signs each denial. What PxDx changes is what the signature covers. The doctor is no longer weighing one claim against one patient's file. The doctor is approving a stack the software has already sorted.

What the software is matters, and Cigna is exact about it. This is code-matching, not a model that learned anything from data. Cigna says the process "works through software (not artificial intelligence or an algorithm)," and that the list covers about 50 low-cost tests and procedures.³ Nothing in PxDx predicts, scores, or estimates. It checks one code against a list and sorts the claim into a pile.

What the reporting found in Cigna's own data

In March 2023, ProPublica and The Capitol Forum published figures drawn from Cigna's internal records. Over two months in 2022, Cigna doctors denied more than 300,000 requests for payment through PxDx. The average time a doctor spent on each was about 1.2 seconds.¹

300,000+denials in two months

1.2 saverage per case

121,000claims, one doctor

The reporters named the doctors and counted their output. In the first two months of 2022, Dr. Cheryl Dopke handled 121,000 of these claims. Dr. Richard Capek handled about 80,000, and Dr. Paul Rossi about 63,000.¹ A former Cigna doctor described the mechanics: "We literally click and submit. It takes all of 10 seconds to do 50 at a time." Dr. Alan Muney, who helped design the system, put the point plainly: "the PXDX stuff is not reviewed by a doc or nurse or anything like that."¹

The person on the receiving end is someone like Suzanne Kisting-Leung, a Cigna member since 2018. A class-action complaint filed in federal court in California in July 2023 lays out her case. Her doctor referred her in August 2022 for a transvaginal ultrasound after flagging a suspected risk of ovarian cancer, and the scan found a cyst. In October, the complaint says, Cigna denied the claim as "not medically necessary" and left her the $198 bill, even though Cigna's own coverage policy calls that ultrasound medically necessary for a woman at increased risk of ovarian cancer.²

Cigna says the software denies payment, not care

Cigna disputes the characterization. It calls PxDx a payment-processing tool, not a gate on treatment. The review runs after the patient has already received care, so no one is turned away from a procedure. A denial through PxDx refuses payment of a specific bill. Correctly coded claims are paid automatically, and Cigna says the software only routes the mismatches to a doctor.³ It called ProPublica's account mischaracterized.⁴

Cigna's account

The post-treatment review process works through software (not artificial intelligence or an algorithm) that matches the codes submitted by the physician with diagnosis codes. Patients are not denied care through this review in any way.³ Cigna Healthcare statement, July 27, 2023

Some of Cigna's objections have force. When the case reached a first ruling in March 2025, the judge found that several named plaintiffs had not shown their own claims were denied through PxDx at all, which is a real limit on the individual stories.⁵ What the objections do not touch is the throughput. Cigna does not dispute the 1.2 seconds or the 300,000 denials, because those figures come from its own data.¹ Whether a denial withholds care or only withholds payment, California law still requires that a qualified person investigate each bill before the insurer refuses it.⁶ A payment denied in about a second is a bill the patient now owes, and the complaint alleges that only about 0.2 percent of policyholders appeal.²

The reporting drew official attention. In May 2023 the House Energy and Commerce Committee wrote to Cigna, asking how PxDx worked and how many claims it had denied, reversed on appeal, or sent to genuine review. The committee noted that in Medicare Advantage plans, where the numbers are public, about 80 percent of appealed coverage denials were overturned.⁷ Insurance regulators in Washington, California, and Delaware opened inquiries.⁴ In March 2025 a federal judge let the core claims proceed, including a finding that Cigna's reading of its plan terms to use PxDx "was an abuse of discretion."⁸ The case is still in discovery.⁵

A signature that reviewed nothing

Meaningful review is a specific thing. It is a qualified person looking at the facts of one case and deciding it on those facts. Its whole job is to catch the case the general rule gets wrong: the ultrasound that is necessary for this patient even when the diagnosis code was not on the list. Take away the individual look and the form of review survives while its function is gone. The denial letter still says a doctor decided.¹ The doctor did sign. But a decision reached in about a second, repeated across 300,000 claims, cannot have weighed 300,000 separate sets of facts.¹

Speed at scale is the tell. When a required human check becomes a formality, the throughput is the evidence, because no reviewer can actually examine cases at that rate. This desk has seen the failure in starker form, in a state system that flagged unemployment fraud and imposed penalties with no human examiner at all. PxDx is the harder version of the same problem. Here the human is present and signs, which is exactly what makes the volume the proof that the signing was empty.

The arrangement is not confined to Cigna. Prior authorization, benefits determinations, and the claims queues that decide what a patient owes all run the same way. Coded rules sort high volumes of requests against fixed lists, and the required human check can shrink to a signature at the end.

The takeaway

PxDx did not fail because a clever model made a subtle mistake. It is not a model. It is a list that matches a procedure to the diagnoses Cigna accepts for it, plus a step where a doctor signs the mismatches into denial. The rule that a qualified person investigate each claim stayed in place. The investigation is what disappeared. When 300,000 denials clear in two months at about a second each, that speed is the record that no one weighed the case in front of them. Cigna disputes the framing, says it denied payment and not care, and a court will sort out the individual claims. The figure it does not dispute is the second per claim, and a second is not long enough to investigate anything. When a required human check meets a volume no human could process, the check becomes a formality, and the same shape is running in the prior-authorization queues that decide what your care costs.

Go deeper optional reading

01: The Capitol Forum and ProPublica, "How Cigna Saves Millions by Having Its Doctors Reject Claims Without Reading Them": the original investigation, with the internal figures in full.
02: KFF, prior-authorization research: how often insurers deny requests, how rarely patients appeal, and how often appeals succeed.

A list matches the procedure to the diagnosis

What the reporting found in Cigna's own data

Cigna says the software denies payment, not care

A signature that reviewed nothing

Sources