Which Doctor Can Testify in a Malpractice Case Depends on What the Claim Is Actually About

When a patient dies after a stretch of medical care, the family's first questions are not legal ones. They are simpler and harder than that. Was this going to happen anyway? Did somebody miss something? Would speaking up sooner have changed anything?

If those questions reach a courtroom, they run into a requirement that surprises most families: a medical negligence claim generally cannot go forward without a doctor willing to say the care fell short. And before the underlying questions get answered, the case often turns to a preliminary one — whether that expert is the right kind of doctor to say it.

In August 2026, the Arizona Supreme Court explained where that argument is supposed to start — and it is not where the courts below started it.

A wound procedure, and a dispute over what came next

A patient entered a skilled nursing facility after a stroke. A physician there evaluated a pressure ulcer on her hip and performed a debridement, removing damaged tissue. Afterward she developed an infection that progressed to sepsis, and she died.

Her mother sued. The heart of the claim was specific: not that the wound procedure was done badly, but that when the patient developed a fever and the infection worsened, the physician failed to recognize it, work it up, and treat it. Her expert — a doctor board certified in internal medicine — said the situation called for further imaging, a surgical consultation, and hospitalization, and that not doing those things fell below the standard of care.

The physician asked the court to end the case. He held the same internal medicine certification, but he also asserted that he was a board certified wound care specialist and that what he had provided was wound care. If that was true, he argued, Arizona law required the family's expert to hold matching wound care credentials — and it did not.

The trial court let the expert testify, finding the care at issue fell within the physician's internal medicine practice. The court of appeals went the other way and directed judgment for the physician. The Supreme Court took the case to sort out how that analysis is supposed to run.

Matching specialties is the second question, not the first

Arizona law requires an expert testifying about the standard of care to have particular qualifications. When the care being challenged falls within the defendant physician's specialty, the expert generally must share that specialty — and if the physician is board certified in it, the expert must be too.

But the Court emphasized something the rule's phrasing makes easy to skip: the requirement only applies when the care at issue was within that specialty. Which means a court has to figure out what the care at issue actually is before it can compare anybody's credentials.

Here, the Court said, the record reflected considerable confusion on exactly that point. The court of appeals had looked at the wound treatment the physician performed. But the family was not complaining about the wound treatment. They were complaining about what came after — the follow-up that they say never happened once the infection took hold.

Those are different medical questions, and they may not belong to the same specialty. By analyzing the treatment that was given rather than the treatment allegedly withheld, the court below answered the wrong question.

Overlap does not dissolve the requirement

It would be easy to read that as a rule favoring families, and the Court headed that off.

If the disputed care does fall within a qualifying board certified specialty the physician was practicing in, the matching requirement still applies — even if a doctor from a different specialty could have competently provided the same treatment. A specialist can also do work that falls outside the specialty as part of a broader practice. Both things are true at once, which is exactly why the question has to be answered case by case rather than by looking at a résumé.

The Court noted it might well turn out that the alleged omissions belong to internal medicine and wound care both. If so, the matching requirement governs.

A claimed certification has to be examined, not just claimed

The Court then addressed something it did not strictly need to reach, because it expected the issue to return: what happens when a physician's certification is itself disputed.

A physician's own description of a credential does not settle whether it counts as a board certified specialty under the statute. Courts have to actually look at it — at whether it reflects materially distinct training and experience, whether it involves an examination and continuing requirements, and the other hallmarks of board certification. Recognition by the American Board of Medical Specialties is not required, and the Court was equally clear that a physician's motives for obtaining a credential are not part of the test.

There is a second requirement that runs in a direction people rarely expect. To invoke these matching rules based on a claimed board certified specialty, the defendant physician must himself have devoted a majority of his professional time to that specialty during the year immediately before the events giving rise to the lawsuit. The qualification inquiry, in other words, looks at both doctors.

What the Court did not decide

The Court identified errors below, vacated the rulings, and set out how the analysis must be redone. What it did not do is resolve the merits — it expressly expressed no view on whether the wound care certification qualifies under the statute.

It vacated the court of appeals' decision. It also vacated the trial court's ruling, because that court's explanation could be read two different ways and there was no way to tell which treatment it had evaluated. The case goes back for the analysis to be done properly.

The Court did not decide whether the certification qualifies, whether the family's expert is ultimately qualified, or whether any medical negligence occurred. All of it is still open.

What does this decision teach us?

• The alleged failure defines the expert question. Care that was never provided can determine the relevant specialty just as much as a procedure that was performed.
• A credential does not control a whole case. Holding a specialty certification does not mean every allegation against that physician falls inside the specialty.
• Overlap runs both ways. If the disputed care is within a qualifying specialty, a matching expert may be required even though other doctors could have provided the same treatment.
• The inquiry looks at both physicians. The expert's credentials matter, and so does whether the defendant's claimed specialty and actual practice meet the statute's requirements.
• Sending a case back is not a finding. This ruling required a clearer analysis before the case can proceed. It decided nothing about whether anyone was negligent.