Toraish v. Lee: Virginia Supreme Court Throws Out Defense Expert's "Differential Diagnosis" in Child's Tonsillectomy Death
Every medical malpractice trial eventually comes down to a battle of experts. And for years, families of malpractice victims have watched defense experts take the stand and offer confident alternative explanations for a catastrophic outcome — theories that shift blame from the doctor's decisions to genetics, bad luck, or an undetectable condition. Last month, the Supreme Court of Virginia sent a clear message: those opinions have to rest on real analysis, not assumption.
The case
Toraish v. Lee, 293 Va. 262, 797 S.E.2d 760, decided April 13, 2017, arose from every parent's worst nightmare. A five-year-old boy underwent an outpatient tonsillectomy. He had severe obstructive sleep apnea — a condition that made breathing complications after surgery a recognized danger. Hours after being sent home, he died.
His family brought a wrongful death case alleging the surgery should have been handled differently in light of the child's severe sleep apnea. At trial, the defense prevailed — largely on the strength of a geneticist's expert opinion that the boy had died not of respiratory compromise after surgery, but of Brugada syndrome, a rare cardiac condition. That opinion was presented as a "differential diagnosis": the expert's conclusion, reached by process of elimination, about what caused the death.
What "differential diagnosis" is supposed to mean
In clinical medicine, a differential diagnosis is a disciplined process: the physician lists every condition that could plausibly explain the patient's presentation, then works through them — testing, examining, consulting the literature — ruling candidates out one by one until the best-supported explanation remains. Done honestly, it is the scientific method at the bedside. In the courtroom, though, the phrase can become a costume: an expert announces that he "performed a differential diagnosis" and arrived at a conclusion, and the methodology's credibility is borrowed without its rigor being applied. The question Toraish squarely answered is whether Virginia courts will look behind the label.
The holding
They will. The Supreme Court of Virginia reversed the defense verdict and ordered a new trial. The problem: the geneticist's differential diagnosis lacked an adequate foundation, because neither he nor any source he relied on had actually ruled out post-operative respiratory compromise — the very cause the family alleged. A differential diagnosis is only as good as its process of elimination. An expert who announces a conclusion without genuinely excluding the competing explanations is not diagnosing; he is speculating. And under Virginia law, expert testimony founded on unsupported assumptions is inadmissible.
Why this matters beyond one case
"Differential diagnosis" testimony is a staple of malpractice defense. It sounds rigorous — it borrows the vocabulary of clinical medicine — and juries understandably give it weight. Toraish holds that the label is not enough. If the methodology claims to work by excluding alternatives, the expert must actually do the excluding, with support, before the jury ever hears the opinion.
The decision cuts in both directions, and honest lawyers will say so: plaintiffs' causation experts must meet the same standard. But in practice, the ruling is a significant tool for injured patients and grieving families, because the speculative-alternative-cause defense is so common. When the defense theory is "something else — something no one could have prevented — killed the patient," Toraish gives trial judges a clear basis to demand the analytical work behind that theory, and to exclude it when the work was never done.
What this means for injured people in Virginia
- Defense experts can be challenged before trial. A well-prepared malpractice team will depose the defense causation expert on exactly what alternatives were considered and how each was excluded, then move to exclude opinions that fail the Toraish standard.
- A defense verdict is not always the end. This family lost at trial and won on appeal because the verdict was built on inadmissible testimony. Appellate review matters in Virginia malpractice cases.
- Cases involving known risk factors deserve special scrutiny. Where a patient carried a documented, elevated risk — like severe sleep apnea before an airway surgery — the question of whether care was adjusted to that risk is at the heart of the case, and defense efforts to explain away the outcome will face a higher bar.
Medical malpractice cases in Virginia are demanding: they require early expert certification, careful compliance with the malpractice statutes, and experts on both standard of care and causation. They also move on evidence that families control in the early days — the complete medical chart, the pre-surgical evaluations, the discharge instructions, the timeline of what was reported to whom and when. Preserving those records promptly, before memories harden and paperwork scatters, is often what makes the later expert battle winnable. Toraish confirms that the playing field has rules, and they bind both sides.
If you or a loved one has been hurt, call Posey Lebowitz at (202) 524-0123 or send us a message for a free consultation.
Part of our DMV case law archive, compiled in 2026 to reflect the archive of some of the most important decisions in injury law.