Minnesota Does Not Pick Between the Reasonable Doctor and the Reasonable Patient. It Uses Both, and You Only Need One.

Every survey of informed consent law sorts the states into two piles. One pile measures disclosure by what a reasonable physician would have told the patient. The other measures it by what a reasonable patient would have wanted to know. Minnesota is regularly filed under the first, and that is wrong in a way that decides cases.

Minnesota uses both, and a plaintiff needs only one. The Supreme Court said so the day it created the claim, and it has never taken it back:

The best accommodation of professional competence and patient self-determination appears to be utilization of both the medical and a modified objective standard of disclosure. Failure to disclose a risk that would have been disclosed under accepted medical practice thus should be a sufficient, but not a necessary, condition of liability.

Cornfeldt v. Tongen, 262 N.W.2d 684, 702 (Minn. 1977) (Cornfeldt I). Sufficient but not necessary. That single sentence is the whole architecture. A defense expert who testifies that no competent surgeon in the community discloses this risk has not won the case; he has only defeated one of the two routes to liability. And a plaintiff who cannot find an expert willing to say the profession requires the disclosure is not out of court, because the patient-materiality route runs independently of the profession’s custom.

I have seen defense counsel treat the professional-standard testimony as dispositive. It is not, and the jury instruction the Supreme Court approved in Kohoutek v. Hafner uses the word “or.”

What is the claim actually called?

It is not “informed consent.” Minnesota’s cause of action is negligent nondisclosure, recognized in Cornfeldt I, decided December 30, 1977 — forty-eight years ago. The court framed it against the older battery theory:

When the patient substantially understands the nature and character of the touching, an action for negligent nondisclosure will lie if the patient was not properly informed of a risk inhering in the treatment, the undisclosed risk materialized in harm, and consent to the treatment would not have been secured if the risk were disclosed.

Cornfeldt I, 262 N.W.2d at 699. The name matters because the two theories carry different proof, different defenses, and — as I explain below — different exposure to the expert affidavit statute.

The three triggers of the disclosure duty

Cornfeldt I set the standard, Cornfeldt v. Tongen, 295 N.W.2d 638 (Minn. 1980) (Cornfeldt II) refined it, and the court has restated the result three times since. Read together, a Minnesota physician must disclose a risk if any one of three things is true:

On the second trigger, Cornfeldt I adopted California’s formulation: “a doctor must also reveal to his patient such additional information as a skilled practitioner of good standing would provide under similar circumstances.” 262 N.W.2d at 702 (quoting Cobbs v. Grant, 8 Cal. 3d 229, 244 (1972)).

The third trigger is where Minnesota parts company with the professional-standard states. Cornfeldt II stated the duty to disclose is established “by evidence establishing that a reasonable person in what the physician knows or should have known to be the patient’s position would likely attach significance to that risk or alternative in formulating his decision to consent to treatment,” and appended a footnote that matters more than the text:

To the extent that our prior opinion suggests that a physician’s duty to disclose extends only to significant risks … it is hereby modified.

295 N.W.2d at 640 & n.2. Notice what the footnote did and did not do. It removed a ceiling; it did not remove a floor. Defense counsel argued the opposite a year later and lost: “This language did not reduce the scope of disclosure delineated in Cornfeldt I.” Kinikin, 305 N.W.2d at 595. The court then laid the three triggers out in a row — risks of death or serious bodily harm “of significant probability,” risks “which a skilled practitioner of good standing in the community would reveal,” and, “to the extent a doctor is or can be aware that his patient attaches particular significance to risks not generally considered by the medical profession serious enough to require discussion with the patient, these too must be brought out.” Id. at 595.

The Supreme Court repeated all three in 1995. K.A.C. v. Benson, 527 N.W.2d 553, 561 (Minn. 1995). Nothing published since has narrowed them.

The disjunction is not my gloss. Kohoutek set out the trial court’s four-condition nondisclosure instruction and approved it, and the second condition is written in the alternative:

First, the physician knew or should have known of a risk of the treatment. Second, standard medical practice would require disclosure of the risk, or the physician knew or should have known that the patient would attach significance to the undisclosed risk. Third, had a reasonable person been informed of the risk she would not have consented to the procedure. And fourth, that the undisclosed risk materialized in harm as a result of the treatment.

383 N.W.2d at 301–02. A plaintiff satisfies condition two either way. That is the case in one word.

Note the shape of the third trigger. It is not the pure reasonable-patient standard of Canterbury v. Spence, 464 F.2d 772 (D.C. Cir.), cert. denied, 409 U.S. 1064 (1972), which Cornfeldt I called “the leading case” for the objective approach, 262 N.W.2d at 700 n.12 — and it is not subjective either. It asks what a reasonable person in the position the physician knew or should have known the patient occupied would find significant. A patient’s idiosyncratic fear does not create a duty by itself — but once the physician is on notice of it, it does. Kinikin is the illustration: the surgeon argued his patient’s cancer phobia excused him from discussing the risk of skin necrosis, and the court answered that a fear of cancer “might, if anything, require Dr. Heupel to devote more time discussing its probability with her, but not to the neglect of other risks which by their dire nature or medical practice require revelation.” 305 N.W.2d at 595.

The five elements, and the one everybody forgets

The Supreme Court’s own enumeration:

(1) a duty on the part of the physician to know of a risk or alternative treatment plan; (2) a duty to disclose the risk or alternative program, which may be established by a showing that a reasonable person in what the physician knows or should have known to be the plaintiff’s position would likely attach significance to that risk or alternative in deciding whether to consent to treatment; (3) breach of that duty; (4) causation (the undisclosed risk must materialize in harm); and (5) damages.

Plutshack v. University of Minnesota Hospitals, 316 N.W.2d 1, 9 (Minn. 1982) (citing Cornfeldt II, 295 N.W.2d at 640).

Element one is a threshold most plaintiffs skate past. A physician cannot disclose a risk he has no duty to know about, so the claim presupposes proof that a reasonably well-trained physician practicing in these circumstances would have known of it. Cornfeldt I, 262 N.W.2d at 699. If the risk was outside the profession’s knowledge, the analysis stops there.

Element four is the one that kills cases. Cornfeldt II reversed a plaintiff’s verdict — after two trials — because no expert would say it was more probable than not that the undisclosed risk caused the death. The court emphasized “that an element of liability is that the undisclosed risk materialize in harm as a result of the treatment.” 295 N.W.2d at 640. In Plutshack, the claim failed because the record showed no evidence that cardiac arrest was a significant risk of a lumbar puncture in a child. 316 N.W.2d at 9. In K.A.C., a family practitioner performed two gynecological procedures without disclosing that he was HIV-positive; the patient tested negative, so the undisclosed and “minuscule” risk of HIV exposure “did not materialize in harm.” 527 N.W.2d at 561. Nondisclosure of a risk that never came true is not a claim, however indefensible the silence.

Is causation measured by what this patient would have done, or what a reasonable one would have?

A reasonable one. Minnesota rejected the subjective test in 1977 and has not revisited it. Cornfeldt I surveyed both approaches, noted that “[a] majority of jurisdictions employs a subjective test of causation,” and went the other way, adopting the objective question: “Whether a reasonable person in the plaintiff’s position would have refused the treatment had he been informed of the undisclosed risk.” 262 N.W.2d at 701. The court’s reasons were candid and practical — it is probably what a jury does anyway when weighing a patient’s testimony, an incapacitated or deceased patient cannot testify at all, and a living patient asked to reconstruct her state of mind after a bad outcome is being asked for “perhaps bitter evaluation.” Id.

Kohoutek stated the rule in one line: “The patient must prove that a reasonable person in the patient’s position would have refused the treatment had the physician disclosed the risk.” 383 N.W.2d 295, 299 (Minn. 1986).

Two consequences follow, and they cut in opposite directions.

The first favors plaintiffs. Your client’s own testimony that she would have declined is not the issue and is not required. Cornfeldt I was a wrongful death case in which the patient could not testify at all, and the court still sent proximate cause to the jury. 262 N.W.2d at 701.

The second favors the defense, and it is underused. Objective causation is defeated by the patient’s actual knowledge. Kinikin laid out proximate cause as two elements — “first, that had a reasonable person known of the risk he would not have consented to treatment; and, second, that the undisclosed risk materialized in harm” — and then added: “If the physician could prove that the patient had actual knowledge of the risk which materialized, then his negligence would be immaterial and the patient’s case would fail.” 305 N.W.2d at 595–96. A patient who had the same operation twice before, or who read the risk in a pamphlet she initialed, has a causation problem that no amount of proof about the doctor’s silence repairs.

Where you need an expert — and where an expert cannot save you

Expert testimony is required for negligent nondisclosure, and it is not required for battery. That single distinction determines whether a case survives the pleading stage.

Cornfeldt I said it plainly: “Expert medical testimony is necessary to establish accepted medical practice and identify the risks of treatment, their gravity, and likelihood of occurrence.” 262 N.W.2d at 702. Kohoutek said the same and drew the contrast:

In battery cases, no expert testimony need be adduced, for the question is whether the physician, in fact, told the patient of the nature and character of the procedure and the patient consented to that procedure.

383 N.W.2d at 299. In a nondisclosure case the question is instead whether the physician should have informed the patient of the risks involved in the procedure — and so, the court held, “the admittance of expert testimony concerning the duty of care in the applicable medical community is necessary.” Id.

What the expert cannot do is prove half of causation. Proximate cause here has two elements — Kinikin, 305 N.W.2d at 595–96 — and they are proved by different means. The first, whether a reasonable person in the patient’s position would have refused, is a jury question; Cornfeldt I refused to take it away as a matter of law even where the defense argued no reasonable patient would have postponed cancer surgery. 262 N.W.2d at 701. The second, that the undisclosed risk materialized in harm, is a medical causation question and needs an expert like any other: “to avoid a directed verdict a plaintiff must introduce expert medical testimony that it was more probable than not that the death resulted from the doctor’s negligence.” Cornfeldt II, 295 N.W.2d at 640. That sentence is why the Cornfeldt plaintiff lost a verdict he had already won. So the expert’s job is the risk — that it existed, that a competent physician would have known of it, how grave it was, how likely it was, and whether custom required its disclosure. The expert does not testify about what the patient would have chosen.

That difference has a procedural consequence the Court of Appeals has flagged: the expert’s role in a nondisclosure case is not the expert’s role in a treatment case, because the two prima facie cases are built out of different elements. Russell v. Johnson, 608 N.W.2d 895, 898 (Minn. App. 2000).

And because negligent nondisclosure requires expert testimony, it falls inside Minn. Stat. § 145.682, subd. 2, which reaches any action against a health care provider “which includes a cause of action as to which expert testimony is necessary to establish a prima facie case.” The affidavit of expert review and the 180-day expert disclosure affidavit both apply. Those mechanics — and the deadlines that are not on your calendar — belong to a separate article on the expert affidavit gate and to the four-year malpractice limitations rules; I will not re-derive them here.

When the procedure was never consented to at all

Then it is a battery, and the analysis changes completely.

The oldest Minnesota case is Mohr v. Williams, 95 Minn. 261, 104 N.W. 12 (1905), overruled in part by Genzel v. Halvorson, 248 Minn. 527, 80 N.W.2d 854 (1957), where the surgeon obtained consent to operate on the right ear and operated on the left. Bang v. Charles T. Miller Hospital, 251 Minn. 427, 88 N.W.2d 186 (1958) extended it: a patient who consented to a prostate operation, without being told that the procedure entailed severing his spermatic cords, had his consent undermined.

Kohoutek drew the boundary that governs today:

In the medical malpractice context, battery consists of an unpermitted touching, in the form of a medical procedure or treatment. The touching is permitted if the patient consents to it. … Consent, however, is not rendered void when a patient is touched in exactly the way to which he or she has consented.

383 N.W.2d at 299. The Supreme Court has since compressed it to a sentence: “In medical malpractice claims, battery consists of touching of a substantially different nature and character from that to which the patient consented.” K.A.C., 527 N.W.2d at 561.

Three practical differences follow, all from Kohoutek at 299. In battery the focus is the patient’s right to be free of a substantially different touching, so “the physician sued in a battery case has very few defenses.” No expert is needed. And causation “is easily proven” — it need only be shown that the procedure performed was substantially different from the one consented to.

That is why plaintiffs reach for battery, and why courts police the line. The Court of Appeals has held that “medical battery cases were limited to substantial and obvious deviations from the anticipated medical procedure or treatment,” Haile v. Sutherland, 598 N.W.2d 424, 428 (Minn. App. 1999), and dismissed a battery claim where the surgeon removed the wrong subcutaneous mass — the intended one was a centimeter across, invisible to the naked eye, and hard to palpate — because the failure rested on “subtle, technical errors rather than a substantial and obvious deviation from the intended procedure.” Id. at 429. The consequence was fatal: “Haile’s battery claim sounds in medical malpractice and must be established through expert testimony,” and it went out under § 145.682 with the negligence count. Id.

The converse is equally true and easier to overlook. A genuine battery claim is not subject to the expert affidavit statute at all. The Court of Appeals said exactly that in December 2024, reversing the dismissal of a medical-battery count that had been swept out with a § 145.682 dismissal: “We are unaware of any authority requiring a plaintiff asserting a medical-battery claim to produce an affidavit of expert review.” Mountjoy v. Fairview Health Services, No. A24-0973 (Minn. App. Dec. 16, 2024). That opinion states on its face that it “is nonprecedential except as provided by Minn. R. Civ. App. P. 136.01, subd. 1(c),” so it binds nobody — but it is the most recent appellate word on the point, and it reads Kohoutek the way Kohoutek reads.

Both theories can be pleaded, but pleading both invites trouble. Kinikin upheld submission of battery and negligent nondisclosure together while warning that in a case turning on the extent of surgery rather than its kind, “it would seem preferable to submit only negligent nondisclosure,” because submitting both “may be redundant and the parties run the risk of an inconsistent verdict.” 305 N.W.2d at 593–94. In Kohoutek the court took the warning further and held it was not an abuse of discretion to refuse a battery instruction where the real complaint was undisclosed risk. 383 N.W.2d at 300.

What does a signed consent form actually prove?

Less than the hospital’s risk manager thinks. It proves a signature. It does not prove that the risk at issue was disclosed, and it does not, standing alone, establish consent.

The proof is in Cornfeldt I itself. The trial court refused an informed consent instruction “on the basis of the record as a whole, specifically citing the consent form signed by Mrs. Cornfeldt and the conversations she had with Dr. Tongen and Dr. Knutson.” 262 N.W.2d at 699. The Supreme Court reversed and ordered a new trial, because the duty the plaintiff was suing on arose after the form was signed, when abnormal preoperative test results came back and nobody told the patient what they meant.

That is the ordinary pattern. A form executed at admission cannot capture a risk that surfaces two days later. A form listing five risks says nothing about the sixth.

Nor does a form settle consent when the circumstances that produced the signature are disputed. Kohoutek held that “[u]nder some circumstances … the patient’s consent can be vitiated,” 383 N.W.2d at 299, and in Kinikin the patient signed a written consent to a “bilateral adenomammectomy” and still took a battery verdict to affirmance, because the evidence conflicted on what that word meant to the parties. 305 N.W.2d at 592–93. In Mountjoy the hospital produced a signed surgical consent and still could not get judgment as a matter of law, because the patient alleged she was “heavily drugged on Ketamine,” “coerced,” and “given no other choice.”

What a good form does is create a documentary record of a conversation. What it cannot do is substitute for one. When I evaluate one of these cases, the form is the fourth document I read, after the operative report, the progress notes on the day the risk was learned, and the medical records that show who knew what and when.

The four places this doctrine does not reach

Negligent nondisclosure is narrower than clients assume, and four decisions mark the edges.

It is not a claim about bad treatment. The Supreme Court could not have been clearer:

The informed consent/nondisclosure doctrine does not involve negligence in the administration of treatment, in failure to treat, or in failure to properly diagnose. Physician liability is imposed by the rule only for failure to secure the patient’s informed consent to treatment which results in harm which the patient would have avoided by declining the treatment or by choosing an alternative treatment.

Madsen v. Park Nicollet Medical Center, 431 N.W.2d 855, 861 (Minn. 1988).

It is not a claim about a diagnosis that turned out wrong. “[M]ere diagnosis, without more, does not give rise to a duty to disclose risks concerning conditions not diagnosed.” Pratt v. University of Minnesota Affiliated Hospitals & Clinics, 414 N.W.2d 399, 402 (Minn. 1987). The court’s reason was that the opposite rule has no stopping point: it would require a physician to tell every patient that the diagnosis might be wrong and to recite the risks of every condition not found. Id. If the diagnosis was negligent, the claim is malpractice, not nondisclosure. Id.

It is not a claim about treatment the patient could have had in addition. “The doctrine of informed consent does not apply to situations where the patient’s decision is whether to submit to treatments in addition to the basic treatment given. Rather, it applies only to situations where the choice is between two or more distinct, alternative methods of treatment.” Kalsbeck v. Westview Clinic, P.A., 375 N.W.2d 861, 869 (Minn. App. 1985), review denied (Minn. Dec. 30, 1985). The Supreme Court applied Kalsbeck to reject the argument that home bed rest versus hospital bed rest was a choice between alternatives — “[a]ny choice would affect only the situs of the patient’s care, not the care itself.” Madsen, 431 N.W.2d at 861.

The affirmative statement of the same boundary: “In Minnesota, informed consent has been applied in two basic situations. First, it applies when the patient must decide between the recommended treatment and no treatment at all. Secondly, it applies when a patient must choose between two or more medically accepted alternative treatments.” Pratt, 414 N.W.2d at 401.

And it is not a second label for the treatment claim you already have. Where a plaintiff cannot articulate a nondisclosure theory that stands apart from the negligent-treatment theory, the district court may refuse to instruct on it at all. Russell, 608 N.W.2d at 899 (“Negligent nondisclosure and negligent care and treatment can overlap at times, but they are different causes of action.”). The plaintiffs in Russell tried and failed to draw the distinction, and their verdict for the defense stood. That fight is won or lost on the special verdict form, which is its own subject and one the malpractice trial procedure article takes up.

Emergencies, incapacity, and the therapeutic privilege

Three separate excuses live here, and they are not interchangeable.

Emergency. The rule predates the tort. A surgeon must obtain consent from the patient or someone authorized to give it “unless an immediate operation is necessary to save the patient’s life or health, although under exceptional circumstances the consent may be regarded as having been impliedly given.” Bang, 251 Minn. at 434. Cornfeldt I carried the exception into the negligence claim in a footnote: “Exceptions that excuse nondisclosure exist for emergency situations, risks commonly known, and the like.” 262 N.W.2d at 700 n.13. And Plutshack applied it — where a child was showing signs of meningitis, the mother could not be located, and a spinal fluid sample was needed quickly, “Christine Plutshack’s actual consent to the first lumbar puncture of May 18 was unnecessary. Consent may be implied.” 316 N.W.2d at 9.

Bang also limits the surgeon who discovers something unexpected mid-procedure. He may extend the operation to remove conditions “which if not removed would endanger the life or health of the patient.” 251 Minn. at 434. Kinikin refused a broader instruction that would have let a surgeon extend an operation whenever “sound professional judgment” called for it, holding that the requested language “goes beyond Bang.” 305 N.W.2d at 593.

Therapeutic privilege. A physician may withhold information when disclosure itself would hurt the patient — but the privilege is narrow, and Minnesota defined it narrowly: it “is applicable only if disclosure of the information would complicate or hinder treatment, cause such emotional distress as to preclude a rational decision, or cause psychological harm to the patient.” Cornfeldt I, 262 N.W.2d at 700. A physician’s judgment that the patient would only be worried, or that the answer was a foregone conclusion, does not qualify; that was precisely the testimony the court found insufficient in Cornfeldt I. And where nondisclosure is warranted, the physician is not excused from obtaining consent — “the physician should seek consent from a close relative.” Id. at 701 n.14. On retrial in Cornfeldt II the jury was asked whether therapeutic privilege justified the nondisclosure and found it did not. 295 N.W.2d at 639–40.

Incapacity. For a civilly committed patient, the Legislature has supplied a procedure, and it was rewritten this year. Read the current text, not the one still sitting on the Revisor’s screen: the 2025 edition is displayed, but 2026 Minn. Laws ch. 95, art. 1, § 12 amended Minn. Stat. § 253B.03, subd. 6, carries no effective-date clause of its own, and therefore took effect under the § 645.02 default before this was written. It reletters every paragraph.

As amended, paragraph (a) is a definitions paragraph, and it is where “proper relative” now lives — “in the following order, the patient’s spouse, parent, adult child, or adult sibling.” Paragraph (b), not (a), carries the right: “A patient has the right to give prior consent to any medical treatment, including but not limited to surgery, other than treatment for chemical dependency or nonintrusive treatment for mental illness.” Paragraph (c), not (b), sets out the procedures for “any treatment necessary to preserve the life or health of any committed patient” — a competent adult patient’s own written informed consent; a guardian’s; and, for a patient in a treatment facility whose head determines the patient is not competent and who has not been adjudicated incompetent, consent from the health care power of attorney, the agent under the health care directive, or the nearest proper relative. Only if that relative cannot be located, refuses, or is unable to consent may the head of the facility or an interested person petition the committing court, or petition for a guardian. § 253B.03, subd. 6(c)(3). New clauses (4) through (6) build a separate track for patients in state-operated treatment programs. The minors clause is now clause (7) and the emergency clause is now clause (8) — they were (4) and (5) before the amendment, and a brief that cites the old numbers is citing a statute that no longer reads that way.

That framework is live, and the Supreme Court construed it this past March — under the paragraph letters as they then stood — in a case about involuntary electroconvulsive therapy: “Generally, under Minn. Stat. § 253B.03, subd. 6(a), civilly committed individuals have the right to consent to medical and surgical treatments, including intrusive mental health treatments such as ECT.” In re Civil Commitment of Graeber, No. A24-0067, slip op. at 2 (Minn. Mar. 11, 2026). Where the patient will not or cannot consent, the court held, the Price/Jarvis balancing test — is the intrusive treatment necessary and reasonable — adequately addresses the statute’s “necessary to preserve the life or health” language. Id. at 21.

Minors. Minnesota’s minor-consent statutes are short and worth knowing verbatim. A minor living apart from parents and managing personal financial affairs “may give effective consent to personal medical, dental, mental and other health services, and the consent of no other person is required.” Minn. Stat. § 144.341. So may a minor “who has been married or has borne a child,” for the minor’s own care or the minor’s child’s. § 144.342. Any minor may consent to services for pregnancy and associated conditions, venereal disease, and alcohol and other drug abuse. § 144.343, subd. 1. And for emergencies:

Medical, dental, mental and other health services may be rendered to minors of any age without the consent of a parent or legal guardian when, in the professional’s judgment, the risk to the minor’s life or health is of such a nature that treatment should be given without delay and the requirement of consent would result in delay or denial of treatment.

Minn. Stat. § 144.344.

The statute that does not set the standard

There is no Minnesota statute defining the physician’s disclosure duty in a negligence case. The one provision that speaks to it points back at the common law. Minn. Stat. § 144.651, subd. 9 — part of the Health Care Bill of Rights — requires that patients “be given by their physicians, advanced practice registered nurses, or physician assistants complete and current information concerning their diagnosis, treatment, alternatives, risks, and prognosis as required by the physician’s, advanced practice registered nurse’s, or physician assistant’s legal duty to disclose.” The statute borrows the duty; it does not create or define it. The Supreme Court made the same observation from the other direction in Pratt, noting that New York’s codification of informed consent “accomplishes no more than case law has done in this state.” 414 N.W.2d at 402 n.2.

Three cautions about relying on the Bill of Rights in litigation.

First, it is tied to a definition, and the definition has moved. In 1989 the Court of Appeals read the statutory term “patient” to require admission “to an acute care inpatient facility for a continuous period of longer than 24 hours” and held that a woman who had surgery at a same-day surgery center was outside the statute entirely. Stubbs v. North Memorial Medical Center, 448 N.W.2d 78, 82 (Minn. App. 1989), review denied (Minn. Jan. 12, 1990). The current definition keeps that 24-hour rule as its baseline but reaches further: for purposes of subdivisions 4 to 9, 12, 13, 15, 16, and 18 to 20 — which include both the information-about-treatment right in subdivision 9 and the experimental-research consent requirement in subdivision 13 — “patient” also means a person who receives health care services at an outpatient surgical center or at a birth center licensed under section 144.615, and separately covers residential and outpatient mental health and substance use disorder settings. § 144.651, subd. 2(a). Check the version of the definition in force on the date of the care, not the one on the screen.

Second, whether it supports a private damages action has never been decided. The Court of Appeals flagged the problem in Stubbs: “We note, without deciding, that there may be no private cause of action available under the Patients’ Bill of Rights,” reasoning that the Legislature created an administrative enforcement mechanism instead of an express private remedy. 448 N.W.2d at 82 n.1. Eight years later the court again declined to decide it. Femrite v. Abbott Northwestern Hospital, 568 N.W.2d 535, 542 n.8 (Minn. App. 1997), review denied (Minn. Nov. 18, 1997). It remains open.

Third, the written-consent requirement in subdivision 13 — “Written, informed consent must be obtained prior to a patient’s or resident’s participation in experimental research” — applies only to experimental research and nothing else. Femrite, 568 N.W.2d at 542.

Femrite is also the answer to the question of who owes the duty. “Generally, a physician has the duty to ensure that a patient gives informed consent.” Id. at 543. The hospital does not: Femrite rejected a corporate-negligence theory that would have put the duty to obtain consent on Abbott Northwestern rather than the surgeons. Id. That is a defendant-selection problem more often than it is a liability theory.

Plead the nondisclosure count in the original complaint or lose it

This is the trap that has cost Minnesota plaintiffs more claims than any doctrinal question above, and it is entirely avoidable.

In Bigay v. Garvey, the plaintiff sued within the limitations period for negligent care and treatment in the performance of surgery, then amended after the period ran to add negligent nondisclosure — that her surgeon never told her his technique was experimental. The Court of Appeals held the amendment related back. The Supreme Court reversed and dismissed the amended complaint. The original pleading “focuses only on the defendants’ actions in performing the surgery itself; it makes no mention of Dr. Garvey’s actions in presurgery consultations, when Bigay’s consent was obtained,” and the nondisclosure allegation “involves separate and distinct conduct” from the surgical negligence. Bigay v. Garvey, 575 N.W.2d 107, 110–11 (Minn. 1998), rev’g 562 N.W.2d 695 (Minn. App. 1997).

Read that against Russell, and the two form a vise. Plead nondisclosure too vaguely at the outset and you cannot add it later; plead it without facts that distinguish it from the treatment claim and the district court will refuse to instruct on it. The way out of the vise is the same in both directions: the nondisclosure count has to be pleaded from a different set of facts — what was said, when, by whom, and what was left out — in the original complaint.

One more damages note. In K.A.C. the majority disposed of the nondisclosure claim on the ground that the undisclosed risk never materialized, over a dissent arguing that the compensable harm in that setting is the patient’s emotional distress. 527 N.W.2d at 561, 563–64 (Page, J., dissenting). If your theory of harm is emotional rather than physical, you are running into Minnesota’s negligent infliction of emotional distress requirements as well, and the informed consent framework will not carry you past them.

What I look for in the first hour of one of these files

1. The operative report and the consent form, side by side. If they describe the same procedure, this is a nondisclosure case, not a battery case, and the § 145.682 clock is running.
2. The date the risk became known to the provider. The duty attaches when the physician knew or should have known. Cornfeldt I, 262 N.W.2d at 699. A risk that surfaced after the form was signed is the strongest version of this claim.
3. Whether the choice was between alternatives or between treatment and none. If it was neither — if the client wanted an additional intervention — Kalsbeck and Madsen end it.
4. Whether the undisclosed risk is the one that actually happened. If the client was not warned about nerve damage and suffered an infection, there is no claim.
5. What the client already knew. Prior identical surgeries, a signed risk sheet, a prior conversation. Actual knowledge is the defense that beats objective causation. Kinikin, 305 N.W.2d at 595–96.
6. An expert who will address the risk, not the outcome. The affidavit must speak to what a competent physician would have known and disclosed. An expert who only says the result was bad has not made the prima facie case.

Madgett Law, LLC

I handle medical negligence and personal injury matters in Minnesota, including claims that turn on what a patient was told before a procedure rather than on how the procedure was performed. That work starts with the records, the consent documents, and an expert review under Minn. Stat. § 145.682 — and it starts early, because the affidavit deadlines and the four-year limitations period do not wait for a client to decide she is angry. If you believe a risk was not explained to you, or you are a lawyer weighing whether a nondisclosure count belongs in a complaint you are about to serve, call 612-470-6529 or Send us a message.

Sources: Cornfeldt v. Tongen, 262 N.W.2d 684 (Minn. 1977) (Cornfeldt I) — at 699 (recognition of negligent nondisclosure; duty to know; battery as a substantially different touching; trial court’s reliance on the signed consent form), at 700 & nn.12–13 (objective disclosure test; Canterbury v. Spence identified as the leading case; therapeutic privilege definition; emergency and commonly-known-risk exceptions), at 701 & n.14 (objective causation test; proximate cause a jury question; consent from a close relative where nondisclosure is warranted), at 702 (both standards, “sufficient, but not a necessary, condition of liability”; Cobbs v. Grant formulation; expert testimony necessary to establish accepted medical practice and identify risks). Cornfeldt v. Tongen, 295 N.W.2d 638 (Minn. 1980) (Cornfeldt II) — at 639–40 (jury finding that therapeutic privilege did not justify nondisclosure), at 640 & n.2 (elements; “reasonable person in what the physician knows or should have known to be the patient’s position”; requirement that the undisclosed risk materialize in harm; modification of Cornfeldt I’s limitation to significant risks). Kinikin v. Heupel, 305 N.W.2d 589 (Minn. 1981) — at 592–93 (written consent to a bilateral adenomammectomy; battery properly submitted), at 593 (instruction that “goes beyond Bang”), at 593–94 (redundancy and inconsistent-verdict warning), at 595 (Cornfeldt II did not reduce the scope of disclosure; the three disclosure triggers; cancer-phobia passage), at 595–96 (two elements of proximate cause; actual knowledge defeats causation). Plutshack ex rel. Plutshack v. University of Minnesota Hospitals, 316 N.W.2d 1 (Minn. 1982) — at 9 (five elements; implied consent in exigent circumstances; failure of proof that the risk that materialized was significant). Kohoutek v. Hafner, 383 N.W.2d 295 (Minn. 1986) — at 299 (battery as unpermitted touching; consent not void where the touching matches the consent; consent may be vitiated; no expert needed in battery, expert necessary in nondisclosure; objective causation), at 300 (refusal of a battery instruction not an abuse of discretion), at 301–02 (approved four-condition nondisclosure instruction, disjunctive “or” between professional custom and patient significance). Pratt v. University of Minnesota Affiliated Hospitals & Clinics, 414 N.W.2d 399 (Minn. 1987) — at 401 (the two situations in which informed consent applies), at 402 & n.2 (diagnosis without more; New York codification accomplishes no more than Minnesota case law). Madsen v. Park Nicollet Medical Center, 431 N.W.2d 855 (Minn. 1988) — at 861 (doctrine does not reach treatment, non-treatment, or diagnosis negligence; situs of care is not an alternative treatment). K.A.C. v. Benson, 527 N.W.2d 553 (Minn. 1995) — at 561 (battery restated; nondisclosure elements; undisclosed risk must materialize in harm), at 563–64 (Page, J., dissenting, on emotional distress as the harm). Bigay v. Garvey, 575 N.W.2d 107 (Minn. 1998), rev’g 562 N.W.2d 695 (Minn. App. 1997) — at 111 (nondisclosure is separate and distinct conduct; amended complaint did not relate back). Bang v. Charles T. Miller Hospital, 251 Minn. 427, 88 N.W.2d 186 (1958) — at 434 (Minn.) (consent required unless immediate operation necessary to save life or health; implied consent; extension of an operation to remove conditions endangering life or health). Mohr v. Williams, 95 Minn. 261, 104 N.W. 12 (1905), overruled in part by Genzel v. Halvorson, 248 Minn. 527, 80 N.W.2d 854 (1957) (operation on the wrong ear). Kalsbeck v. Westview Clinic, P.A., 375 N.W.2d 861 (Minn. App. 1985), review denied (Minn. Dec. 30, 1985) — at 869 (additional treatment versus distinct alternative methods). Stubbs v. North Memorial Medical Center, 448 N.W.2d 78 (Minn. App. 1989), review denied (Minn. Jan. 12, 1990) — at 82 (same-day surgery patient outside the § 144.651 definition), at 82 n.1 (no private cause of action may exist under the Patients’ Bill of Rights). Femrite v. Abbott Northwestern Hospital, 568 N.W.2d 535 (Minn. App. 1997), review denied (Minn. Nov. 18, 1997) — at 542 & n.8 (subdivision 13 limited to experimental research; private cause of action not decided), at 543 (the physician, not the hospital, owes the duty to obtain informed consent). Haile v. Sutherland, 598 N.W.2d 424 (Minn. App. 1999) — at 428 (medical battery limited to substantial and obvious deviations), at 429 (battery claim resting on subtle technical error sounds in malpractice and requires expert testimony under § 145.682, subd. 2). Russell v. Johnson, 608 N.W.2d 895 (Minn. App. 2000) — at 898 (elements; the expert’s role differs because the prima facie cases differ), at 899 (nondisclosure and negligent treatment are different causes of action; refusal to instruct affirmed). Mountjoy v. Fairview Health Services, No. A24-0973 (Minn. App. Dec. 16, 2024) (nonprecedential except as provided by Minn. R. Civ. App. P. 136.01, subd. 1(c)) — slip op. at 8–9 (no authority requires an affidavit of expert review for a medical-battery claim; signed consent form did not resolve disputed consent). In re Civil Commitment of Graeber, No. A24-0067 (Minn. Mar. 11, 2026) — slip op. at 2 (right to consent under Minn. Stat. § 253B.03, subd. 6(a)), slip op. at 21 (Price/Jarvis balancing test adequately addresses “treatment necessary to preserve the life or health”); quoted from the opinion body, not the syllabus. Minn. Stat. § 144.651, subd. 2(a) (definition of “patient”), subd. 9 (information about treatment, “as required by the physician’s … legal duty to disclose”), subd. 12 (right to refuse care based on the subdivision 9 information), subd. 13 (written informed consent for experimental research). Minn. Stat. § 144.341 (minor living apart from parents), § 144.342 (minor who has married or borne a child), § 144.343, subd. 1 (minor’s consent for pregnancy, venereal disease, and substance abuse services), § 144.344 (emergency treatment of minors). Minn. Stat. § 253B.03, subd. 6, as amended by 2026 Minn. Laws ch. 95, art. 1, § 12 (consent for medical procedure; relettered paragraphs (a)-(d); substitute decisionmakers at subd. 6(c); minors clause (7); emergency clause (8)); Minn. Stat. § 645.02 (default effective date of an act that specifies none). Minn. Stat. § 145.682, subds. 1–4 (expert review affidavit requirement, triggered where expert testimony is necessary to establish a prima facie case). This article is general legal information about Minnesota law. It is not legal advice, it does not create an attorney–client relationship, and no outcome is promised or implied.