Today’s guest post is from Dechert’s Brooke Meadowcroft who brings us her take on an unfortunate learned intermediary ruling out of Illinois. As always, our guest posters deserve 100% of the praise (and any of blame) for their posts. Not that we expect the latter. 

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The learned intermediary doctrine is the elegant legal principle that says when it comes to prescription drugs and medical devices, the manufacturer satisfies its duty to warn by informing the prescribing doctor—not the patient—because, well, four years of medical school and three years of residency trump three hours on WebMD. But apparently, some courts think that when a plaintiff brings a consumer fraud claim (as opposed to a failure to warn claim), the learned intermediary doctrine need not apply. And with that, the curtain falls on logic.

Ignoring state court decisions interpreting the Illinois Consumer Fraud and Deceptive Business Practices Act (“ICFA”) on this very issue, the Northern District of Illinois, in Swieczkowski v. BillionToOne, Inc., recently ruled that the learned intermediary doctrine was not a bar to the plaintiffs’ ICFA claim. 2025 WL 2483345, at *3 (N.D. Ill. Aug. 28, 2025).

In Swieczkowski, the plaintiffs brought various claims against the defendant, which produced a non-invasive prenatal test that allegedly screened for chromosomal abnormalities and is only available by prescription. Id. at *1. The “Unity Complete Test” (“Unity Test”) included a screening for Trisomy 18, a fatal chromosomal disorder. Id. Plaintiffs allege their physician was marketed the Unity Test by the defendant and shown advertising materials that included a representation that the test had a 99.9% sensitivity rate. Id. The plaintiffs’ physician recommended the plaintiffs undergo the test, which they did. Id.

The results of the Unity Test showed that the fetus’s risk of having Trisomy 18 was less than 1 in 10,000. Id. at *2.However, when the plaintiffs’ child was born a few months after the test was administered, a blood test revealed that the child had Trisomy 18. Id. The child later passed away from complications from the condition. Id.

The plaintiffs alleged that the Unity Test’s results were misleading and false because the 1 in 10,000 risk calculation failed to account for the risk of a false negative, and the defendant’s own study allegedly revealed a false negative rate much higher than .0001. Id. The plaintiffs also asserted that the 1 in 10,000 figure was also false and misleading as it indicated that the Unity Test was diagnostic, when it was actually just a screening tool. Id. The plaintiffs alleged violations of the ICFA and common law claims of fraud and negligent misrepresentation in their lawsuit against the company. Id. at *1.

The defendant, in its motion to dismiss the plaintiffs’ suit, alleged that the plaintiffs’ claims were barred under the learned intermediary doctrine because the limitations associated with screening tests are well known in the medical community. Id. at *2.

The court denied the defendant’s assertion that the learned intermediary barred the plaintiffs’ claims. First, the court stated the defendant did not cite any caselaw where an Illinois court applied the doctrine to an ICFA claim (more on this later). Id. at *3. The court differentiated between the defendant’s cited caselaw, which focused on applying the doctrine when evaluating product liability actions based on a failure to warn theory, versus the plaintiffs’ claims, which relied on a fraud/misrepresentation theory. Id. Thus, the learned intermediary doctrine couldn’t apply here as the plaintiffs weren’t claiming that the Unity Test posed safety/use risks. Id. While the court later denied the defendant’s motion to dismiss, finding that the plaintiffs’ claims were sufficiently supported by the alleged facts, id. at *6, the real absurdity of Swieczkowski is its conclusion that the learned intermediary doctrine is completely irrelevant in the context of the ICFA (and other state consumer protection laws).

The distinction between consumer fraud and failure to warn in the prescription product context is a legal fiction so thin, it would make a Hollywood scriptwriter blush. The whole point of the learned intermediary doctrine is that in the prescription drug universe, manufacturers communicate warnings and representations to doctors, not patients. Whether those representations involve risks or benefits, side effects, or odds of success, the target audience is the same: the learned intermediary. The patient is not relying on representations by the manufacturer, something which is a core element of causation in any fraud claim. But rather, the patient relies on the physician to apply his/her training, experience, and knowledge to interpret the information provided by the manufacturer, among other sources of data. The learned intermediary breaks the causal nexus.

Rest assured, Swieczkowski does state that in cases involving products liability actions, the doctrine will be more applicable than in a pure fraud/marketing misrepresentation case. So drug/medical device manufacturers can breathe a sigh of relief knowing that at least the doctrine is alive and well in Illinois for failure to warn claims. But in so ruling, the court completely overlooked decisions both by Illinois state courts and federal courts applying Illinois law that have already applied the learned intermediary doctrine to ICFA claims, as we’ve discussed and cited here before. In so doing, Swieczkowski violates a fundamental rule of diversity jurisdiction: federal courts cannot alter the state laws they’re applying, as doing so would run afoul of the Erie doctrine. Which, as much as lawyers would like to avoid Erie and its many complexities, is unconstitutional. Allowing otherwise would let federal courts completely rewrite state laws, creating a Wild West of forum shopping and judicial activism for state consumer protection laws.

So really, there should be no battle on this issue. It has been decided. Unfortunately, by pretending that consumer fraud claims in the context of prescription products are meaningfully different from failure-to-warn claims, Swieczkowski has turned the Land of Lincoln into a land of legal opportunism. It incentivizes artful pleading over honest lawyering where plaintiffs who know they can’t outrun the learned intermediary doctrine, slap a consumer fraud label on their claim and are back in business. If semantics are allowed to override substance, we risk turning the learned intermediary doctrine into the ignored intermediary doctrine, and that’s just bad law.