Hepatology Expert’s Testimony About an Increased Risk of Liver Cancer Admitted

Posted on July 9, 2025 by Expert Witness Profiler

Wexford Health Sources, Inc. was the company hired by the State of Illinois to provide medical care to inmates across the state’s prison system. One of those inmates, Paul Daval, filed a lawsuit against certain Wexford employees, accusing them of showing deliberate indifference to his serious medical condition. Daval alleged that while he was incarcerated at Dixon Correctional Center, the staff knew he had chronic Hepatitis B and serious liver damage—but still failed to provide timely treatment. As a result, his health reportedly worsened due to the delay.

Daval’s retained opinion witness Dr. Nancy Reau concluded (among other things) that Wexford’s course of treatment “most likely” caused Daval to develop liver cirrhosis, severe symptoms, and an increased risk of liver cancer. Defendants filed motion to bar these conclusions under the Daubert standard.

Hepatology Expert Witness

Dr. Nancy S. Reau has over twenty years’ experience treating viral hepatology and currently serves as the Chief of Hepatology at Rush University Medical Center.

Want to know more about the challenges Nancy Reau has faced? Get the full details with our Challenge Study report.

Discussion by the Court

Reau’s 26(a) report details Daval’s treatment history and condition before attributing his risk of cancer to “ongoing hepatocellular injury with hepatic necrosis resulted in fibrosis and, because it was not controlled, cirrhosis.”

According to Reau, properly treating Daval beginning shortly after he tested positive for hepatitis B would have significantly reduced the likelihood of Daval developing cirrhosis, because cirrhosis happens progressively over a long period of time in response to a hepatitis B infection.

The Court held that the Defendants wrongly asserted that Reau relied “only” on Daval’s fatigue in reaching her conclusion, when her deposition testimony indicated she also knew he suffered from nausea and “a lot of musculoskeletal issues.”

In assorted causal challenges to Reau’s conclusions, the Defendants contended that she failed to account for relevant variables, failed to obtain a control sample, and ultimately reached the opposite conclusion than their own expert.

The Court held that the Defendants’ causal challenges are all factual matters necessarily reserved for the trier of fact or, if appropriate, on summary judgment. As a result, Reau may opine on whether the Defendants’ delay contributed to Daval’s symptoms, cirrhosis, and risk of liver cancer, consistent with her report and subject to “[v]igorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof.”

Held

The Court denied the Defendants’ motion to limit the testimony of Plaintiff’s expert, Dr. Nancy Reau.

Key Takeaway:

Reau’s report provided a rational connection between Wexford’s medical treatment and Daval’s cirrhosis, symptoms, and risk of liver cancer. Whether it definitively proved those relationships, however, falls outside the scope of Daubert.

Daubert, after all, is concerned with methodology that experts use, not the conclusions experts reach.

Case Details:

Case Caption:Daval V. Zahtz Et Al
Docket Number:3:21cv50405
Court Name:United States District Court, Illinois Northern
Order Date:July 08, 2025