An emergency room doctor telephoned defendant (an on-call neurosurgeon) to ask his advice about plaintiff, who had come into the emergency room for treatment. When plaintiff later sued defendant for malpractice, the jury returned a verdict in defendant’s favor; the jury found that defendant was not acting as plaintiff’s doctor and, as a result, owed her no duty. The Court of Appeals reversed, holding that the trial court should have directed a verdict in plaintiff’s favor on that issue. Mead v. Legacy Health System, 231 Or App 451, 464, 220 P3d 118 (2009). We allowed defendant’s petition for review to consider that issue. Because we conclude that, on this record, the jury could find that defendant was not acting as plaintiff’s doctor, we uphold the trial court’s ruling denying plaintiff’s motion for a directed verdict. We also conclude, however, that the trial court erred in instructing the jury and, for that reason, agree that the case must be remanded for a new trial.1
The relevant facts can be summarized briefly.2 On July 1, 2002, defendant was the on-call neurosurgeon for Legacy Good Samaritan and Legacy Emanuel Hospitals. That day, defendant received a telephone call from a male resident, asking for advice about a patient who had come into the emergency room. The resident told defendant that
“they had a patient who [had come into the emergency room who] had bad back pain, who was neurologically intact, who had [an] MRI with a disk bulge and who had normal rectal tone.”
*270Defendant understood that the resident was “ask[ing] for [his] advice *** to determine at this time whether the patient needs to be seen by a neurosurgeon,” and defendant’s advice was “to admit the patient to the medical service for pain management.” Defendant testified at trial that, based on the information that the resident had provided him, he concluded that the patient did not need neurosurgery at that time — -a conclusion that was implicit in his advice to admit the patient for pain management. The resident did not ask defendant to see the patient, and defendant testified that he did not “do anything or say anything to communicate to the resident that [he was] somehow going to embark and become involved in the treatment of this patient [.]”
Consistently with his statement that he did not do or say anything to become involved in plaintiff’s treatment, defendant did not admit plaintiff to the hospital under his care. Rather, plaintiff’s primary care physician, Dr. Kisor, admitted plaintiff to the hospital under her care. (At Legacy, the physician who admits a patient to the hospital is responsible for the patient’s care.) Later that day, plaintiff’s condition worsened, and Kisor asked a neurologist, Dr. Leonard, for his assistance. Leonard previously had treated plaintiff for migraine headaches, and he consulted with Kisor to determine the cause of plaintiff’s worsening condition. Their attempts to determine the cause of plaintiff’s condition were not successful, and her condition continued to deteriorate over the next few days.
On July 4, Kisor’s nurse called defendant to ask if he would see plaintiff. The nurse did not say that the request was urgent, and defendant asked the nurse to have Kisor call him. Defendant did so for two reasons. As a general matter, when asked to see another doctor’s patient, defendant’s practice is to speak with the doctor first so that he can ask the doctor questions about the patient’s condition. Additionally, and specific to this case, Kisor’s nurse told defendant that Kisor was concerned that plaintiff might have a conversion disorder. Because a conversion disorder is a psychological condition that neurosurgeons ordinarily do not treat, defendant did not understand why Kisor would ask for his help with that problem and wanted to speak with her before seeing plaintiff.
*271Kisor called defendant on July 5. After talking with her, defendant saw plaintiff that day. On examining plaintiff, defendant diagnosed plaintiff as suffering from cauda equina syndrome; specifically, defendant concluded that the MRI taken on July 1 showed that plaintiff had a herniated disk, not a disk bulge as the resident had reported. He also concluded from his review of the MRI and his examination of plaintiff that pulp from the center of the herniated disk had escaped and was pressing on a sheath of nerves (the cauda equina) that govern a person’s ability to move their legs and to control their bladder and bowel functions. Defendant operated immediately to remove the pressure. The operation was successful. However, the delay between the onset of the pressure and its removal resulted in substantial damage to the nerves governing plaintiff’s ability to control her legs and her bladder and bowel functions.
As a result of that damage, plaintiff filed an action against Legacy for the negligence of its employees and also against Leonard.3 Later, plaintiff filed a second amended complaint, adding defendant and alleging that he had negligently failed to “timely diagnose, treat and care for plaintiff’s low back condition,” “timely examine plaintiff,” “timely review plaintiff’s MRI,” and “timely respond to requests for consultation regarding plaintiff’s low back condition.” Plaintiff’s claim against defendant rested on the premise that, as a result of the telephone call defendant received on July 1, defendant had entered into a physician-patient relationship with plaintiff and, as a result, owed her a duty of due care. Plaintiff acknowledged that, if defendant did not enter into a physician-patient relationship with her until Kisor called him on July 5, then she had no claim against him.
Approximately three weeks before the trial began, plaintiff entered into covenants with Legacy and Leonard not to execute on any judgment against them in return for a payment of $4 million. The agreements provided that, if plaintiff recovered more than $3 million from defendant, she *272would return $100,000 each to Legacy and Leonard. Although the covenants contemplated that Legacy and Leonard would remain as defendants in plaintiff’s action and participate as such at trial, the trial court ruled that, as result of entering into the covenants, no justiciable controversy remained among plaintiff, Legacy, and Leonard. Accordingly, it dismissed both Legacy and Leonard as defendants.
The case went forward solely against defendant. One of the issues at trial was whether defendant had entered into a physician-patient relationship with plaintiff on July 1. Both sides offered expert testimony on that issue, and each side’s expert based his opinion on different testimony regarding what had happened that day. To help put the experts’ testimony in perspective, we briefly discuss a factual dispute that informs each expert’s opinion.
As noted, defendant testified that, on July 1, he had received a telephone call from a male resident working in the emergency room and that the male resident had told him the information quoted earlier in this opinion. An emergency room doctor, Aviva Zigler, had examined plaintiff when she came to the emergency room. Zigler testified that, after examining plaintiff, she had called defendant on July 1 and had spoken to him personally. According to Zigler, she told defendant more (and sometimes different) information about plaintiff than the male resident had told him. Zigler also testified that, although she had not explicitly asked defendant to see plaintiff, she believed that that request was implicit in her calling him in the first place. Defendant, for his part, testified that he had not spoken with Zigler but had received a call from a male resident.
With that background in mind, we turn to the experts’ opinions as to whether defendant entered into a physician-patient relationship with plaintiff on July 1 as a result of a call either from the male resident or Zigler. Dr. Hacker, a neurosurgeon, testified as an expert witness on behalf of defendant. When asked whether, “[i]n your judgment and based upon your training and experience, was there a physician-patient relationship between [defendant] and [plaintiff] over the period [from] July 1 until [defendant] saw her on July 5,” Hacker replied, “I didn’t *273see a doctor-patient interaction or relationship [between defendant and plaintiff] until * * * July 5.”4
Hacker explained that an on-call physician will have an obligation to see and provide medical services to another doctor’s patient in two situations. The first situation occurs when the emergency room physician or another doctor asks the on-call physician for a consultation or, more colloquially, to see the patient. As Hacker explained,
“[A] consultation is very simply obtained. Somebody over the phone will say to me, ‘[doctor], I want you to see my patient’ or ‘[doctor], I want you to see this patient.’ And that’s in some regard, when I’m on-call for the emergency room or when I’m in a hospital where I have privileges, it’s stipulated by the by-laws that I am then obligated to help out. There is no saying, ‘Well, I can’t do this’ or T won’t do that.’ The minute the doctor says, ‘[doctor], I want you to see this patient,’ the answer is, Tes, I’ll be happy to.’ And that’s always the answer because that’s the rules.”
The second situation occurs, according to Hacker, if “the [on-call] physician had enough information on his [or her] own to conclude this is a patient that I should see.” According to Hacker, in both situations, an on-call physician will have an obligation to see and treat another doctor’s patient.
Regarding the first situation that Hacker identified, defendant testified that the resident with whom he spoke did not ask him to see plaintiff or provide medical services to her. According to defendant, the resident asked for advice only as to whether the patient needed to be seen by a neurosurgeon. Regarding the second situation, there was evidence from which the jury could have found that the information defendant received from the resident would not have put a reasonable neurosurgeon on notice that “this is a patient [whom he] should see.” Specifically, the jury could have found that the information that defendant received from the resident omitted three critical facts that would have alerted a reasonable neurosurgeon that plaintiff could have, cauda equina syndrome instead of common back pain.5
*274Plaintiffs expert, Dr. Kendrick, agreed, in part, with defendant’s expert. For example, Kendrick testified on direct examination:
“[W]hen a neurosurgeon is on call for *** a hospital, and receives a call from an emergency room doctor, a certain obligation is developed. And we as neurosurgeons, when we are on call and get such a call, have to respond, first of all. And if we’re asked to see a patient, then we’re obligated to undertake the care of that patient and a physician-patient relationship is established per se by the ER physician asking us to see someone.”
Consistently with his testimony on direct examination, Kendrick agreed on cross-examination that the “threshold issue, so to speak, [for establishing a physician-patient relationship] is [whether] the emergency room physician request[s] a neurosurgical consultation with [defendant].” Kendrick also testified, as Hacker had, that, if the emergency room physician described sufficient symptoms of a neuro-surgical condition, an on-call neurosurgeon would have an obligation to examine the patient and thus undertake the patient’s care.
Kendrick agreed that the emergency room physician had not expressly asked defendant to see plaintiff. However, he opined that, in effect, the “emergency room physician was requesting that [defendant] become involved in [plaintiff’s] care.” He also concluded that the symptoms that the emergency room physician identified were sufficient to require defendant to see and examine plaintiff. It is worth noting that, when Kendrick referred to the “emergency room physician,” he appears to have been referring to Zigler, who testified that she had called defendant personally on July 1 to ask for his assistance in treating plaintiff; that is, Kendrick’s opinion relies on and tracks Zigler’s testimony *275regarding the call that she supposedly made to defendant on July 1.
Not only did the two experts reach different conclusions regarding whether the facts gave rise to an obligation on defendant’s part as the on-call neurosurgeon to see and provide treatment to plaintiff, but each expert appears to have based his opinion on a different set of facts. Hacker appears to have based his opinion primarily on defendant’s testimony, and Kendrick appears to have based his opinion primarily on Zigler’s testimony. As noted, the jury found that defendant had not entered into a physician-patient relationship with defendant on July 1, and the trial court entered judgment in defendant’s favor based on that finding.6
The Court of Appeals reversed, holding that the only conclusion that the jury could have reached on this record was that a physician-patient relationship existed on July 1. See Mead, 231 Or at 463-64. The Court of Appeals recognized that, without a physician-patient relationship, defendant owed no duty to plaintiff. Id. at 457. It also recognized that the formation of that relationship is consensual and that the parties’ consent to enter a physician-patient relationship may be either express or implied. Id. at 458. In this case, the Court of Appeals found that defendant impliedly consented to enter into a physician-patient relationship from the combination of two facts. See id. at 463-64. It concluded that, in advising the resident to admit plaintiff for pain management, defendant was diagnosing plaintiff. Id. at 463. It also observed that, in doing so, defendant was acting in his capacity as an on-call physician. It followed from those two facts, the Court of Appeals reasoned, that defendant’s “advice * * * was not merely casual or informal advice to a colleague [but instead was] a diagnosis directed to a specific patient.” Id. at 464. The Court of Appeals held that, because defendant formally had undertaken to diagnose plaintiff, he had entered into a physician-patient relationship with her. Id.
*276On review, plaintiff commends the Court of Appeals’ reasoning to us. Alternatively, she contends that the trial court erred in instructing the jury on when a physician-patient relationship will arise and also in permitting defendant to impeach her witnesses based on the covenants that either they or their employer entered. We begin with the question that the Court of Appeals decided — whether there was any evidence in the record to support the jury’s verdict. Regarding that question, we will “uphold the jury’s verdict, unless our review of the record reveals that there is no evidence from which the jury could have found the facts” necessary to sustain its verdict. See Northwest Natural Gas Co. v. Chase Gardens, Inc., 333 Or 304, 310, 39 P3d 846 (2002) (stating that standard).
We begin by setting out the governing legal principles. In Oregon, as in most states, a physician-patient relationship is a necessary predicate to stating a medical malpractice claim. See Dowell v. Mossberg, 226 Or 173, 181-83, 355 P2d 624, rev’d on reh’g on other grounds, 359 P2d 541 (1961); David W. Louisell & Harold Williams, 1 Medical Malpractice § 8.03 [1] at 8-17 (2009) (summarizing decisions from other states). As this court recognized in Dowell, without a physician-patient relationship, “‘there c[an] be no duty to the plaintiff, and hence no liability.’ ” Dowell, 226 Or at 181-82 (quoting Currey v. Butcher, 37 Or 380, 385, 61 P 631 (1900)).7
A physician-patient relationship may be either express or implied. See Dowell, 226 Or at 182. In this case, plaintiff does not contend that defendant expressly agreed to provide medical services to her. Rather, she contends that an implied physician-patient relationship arose when defendant offered an opinion regarding her condition to the emergency room resident on July 1.
*277When a patient goes to a doctor’s office and the doctor examines the patient, ordinarily no one disputes that an implied agreement to provide medical care has been formed and that consequently an implied physician-patient relationship arises. Cf. Lyons v. Grether, 239 SE2d 103, 105 (Va 1977) (holding that an appointment for a specific illness permitted a reasonable inference that the defendant had agreed to provide medical services for that illness and thus provided a basis for inferring a physician-patient relationship). That is, we infer from the parties’ actions, considered in light of the customary practice in the medical community, that the physician consented to provide and the patient consented to receive medical services. Cf. White v. Jubitz Corp., 347 Or 212, 234, 219 P3d 566 (2009) (explaining when an implied contract to pay the costs of medical treatment will arise).
Historically, an implied physician-patient “relationship [has been] limited to physicians seen directly by the patient; the physician-patient relationship typically does not exist between the patient and physicians consulted by the patient’s personal physician.” Louisell & Williams, 1 Medical Malpractice § 8.03[2] [a] at 8-19 - 8-22 (footnotes omitted). More recently, however, courts have recognized that “[t]he fact that a physician does not deal directly with a patient does not necessarily preclude the existence of a physician-patient relationship.” St. John v. Pope, 901 SW2d 420, 424 (Tex 1995); see McKinney v. Schlatter, 692 NE2d 1045, 1050-51 (Ohio Ct App 1997), overruled on other grounds by Lownsbury v. VanBuren, 762 NE2d 354, 362 (Ohio 2002) (holding that it was a question of fact for the jury whether an on-call cardiologist who had discussed a patient’s symptoms and test results with an emergency room physician entered into a physicián-patient relationship with the person seeking treatment). As one court has observed,
“In light of the increasing complexity of the health care system, in which patients routinely are diagnosed by pathologists or radiologists or other consulting physicians who might not ever see the patient face-to-face, it is simply unrealistic to apply a narrow definition of the physician-patient relationship in determining whether such a relationship exists for purposes of a medical malpractice case.”
*278Kelley v. Middle Tennessee Emergency Physicians, 133 SW3d 587, 596 (Tenn 2004); cf. Eads v. Borman, 351 Or 729, 743-44, 277 P3d 503 (2012) (noting that changes in the way health care is delivered affect apparent agency analysis); id. at 759-60 (De Muniz, C. J., specially concurring) (same).
As the court recognized in Kelley, with increasing specialization in the medical profession, hospitals or medical groups may divide responsibility for providing medical services among a team of physicians, with some of the physicians responsible for performing only discrete medical services for the patient. A radiologist, for example, may interpret a patient’s x-rays and relay that interpretation to the patient’s primary care physician, who uses the radiologist’s interpretation to determine the course of the patient’s treatment. That division of responsibility for the patient’s care may arise as a result of custom or practice, without a formal referral or request for consultation. Faced with that division of services, some courts have sought to determine when a physician who has not personally examined a patient will enter into an implied physician-patient relationship by asking whether the physician has undertaken to provide a particular medical service to a patient. In Kelley, the court explained that “a physician-patient relationship may be implied when a physician affirmatively undertakes to diagnose and/or treat a patient, or affirmatively participates in such diagnosis and/or treatment.” 133 SW3d at 596.
The standard articulated in Kelley depends, as an initial matter, on classifying a physician’s actions as either the “diagnosis” or the “treatment” of a patient’s condition. Some tasks that physicians perform, such as interpreting an x-ray, may be relatively easy to classify. Others, such as diagnosis, may pose more difficulty. As explained below, not every opinion that one physician offers another constitutes a diagnosis; indeed, the same statement may be a diagnosis when made in one context but not when made in another. That is, the question whether a physician’s expression of an opinion constitutes a diagnosis will vary depending on, among other things, the customary practice within the relevant medical community, the degree and the level of formality with which one physician has assumed (or the other physician *279has ceded) responsibility for the diagnosis or treatment, the relative expertise of the two physicians, and the reasonable expectations, if any, of the patient under the circumstances.
In our view, the standard should not be whether a judge or a jury would classify a statement as a diagnosis or the provision of treatment. Rather, it should be whether a physician who has not personally seen a patient either knows or reasonably should know that he or she is diagnosing a patient’s condition or treating the patient. If the jury finds that, in light of the factors identified above, the physician either knew or reasonably should have known that he or she was diagnosing the patient’s condition or providing treatment to the patient, then an implied physician-patient relationship exists and the physician owes the patient a duty of reasonable care.
With that standard in mind, we turn to plaintiff’s argument that the trial court erred in denying her motion for a directed verdict. Her argument on that point starts from the proposition that two facts are undisputed: (1) in response to the resident’s telephone call on July 1, defendant offered his opinion that plaintiff should be admitted to the hospital for pain management and (2) in offering that opinion, defendant was acting in his capacity as the on-call neurosurgeon. It necessarily follows from the combination of those two facts, plaintiff contends, that defendant was undertaking to diagnose her condition and, in doing so, entered into a physician-patient relationship with her.
Regarding the first fact on which plaintiff relies, the courts consistently have held that merely providing advice to a colleague about that colleague’s patient does not give rise to a physician-patient relationship. See, e.g., Irvin v. Smith, 31 P3d 934, 941 (Kan 2001); Reynolds v. Decatur Mem’l Hosp., 660 NE2d 235, 238-39 (Ill App Ct 1996); see also Oliver v. Brock, 342 So 2d 1, 4 (Ala 1976). That is true even though the patient’s doctor has discussed the patient’s symptoms and test results with another physician and the physician has offered advice to the patient’s doctor about the possible cause of the patient’s condition and the proper course of treatment. See id.
The Illinois Appellate Court’s decision in Reynolds is illustrative. In that case, the parents of a two-year-old *280brought their child into the hospital emergency room. Reynolds, 660 NE2d at 237. The child’s temperature was 102 degrees, his body was flaccid from the neck down, and he was having difficulty breathing. Id. The parents reported that their child had jumped off a couch and landed on his arm. Id. The emergency room doctor called a colleague, Dr. Fulbright, for his advice. Id. at 237 She described the child’s symptoms to Fulbright, who ■ testified that they discussed potential causes for those symptoms, ranging from child abuse to meningitis to ascending neuritis, and “[w]e elected to proceed with the plan of [the emergency room doctor’s] performing [a] lumbar puncture and [her] letting me know if she needed me there.” Id.
When the child suffered severe complications, his parents sued Fulbright for malpractice, and the Illinois Appellate Court upheld a decision granting summary judgment in Fulbright’s favor. See id. at 236. The court held that Fulbright had merely offered an opinion to the emergency room doctor about the possible causes and treatment of the child’s condition; that act was not sufficient to give rise to a physician-patient relationship between Fulbright and the child. Id. at 239. The court was careful to note the limits of its holding, however. It reasoned:
“[T]his is not a case in which Fulbright was asked to provide a service for [the child], conduct laboratory tests, or review test results. Fulbright did nothing more than answer an inquiry from a colleague. * * * A doctor who gives an informal opinion at the request of a treating physician does not owe a duty of care to the patient whose case was discussed. * * * This is not a case in which Fulbright had accepted a referral of the patient. *** Nor is this a case in which a physician undertook to direct the actions of hospital employees in a telephone conversation with an emergency room nurse.”
Id. (citations omitted).
We agree with the decisions from other states that advising a colleague about the possible causes of a patient’s illness or the proper course of treatment for a patient does not necessarily give rise to an implied physician-patient relationship.8 Put differently, in light of the customary *281practice in the medical profession, the fact that one doctor offers an opinion to a colleague about that colleague’s patient does not necessarily mean that the doctor either knows or should know that he or she is rendering a diagnosis for the patient, as opposed to offering advice to a colleague.
Plaintiff does not appear to dispute that proposition. That is, plaintiff does not contend that, if defendant had made the same statement to the resident — to admit plaintiff to the hospital for pain management — in a different context, the jury would be required to find that defendant was diagnosing plaintiff’s condition, as opposed to offering advice to a colleague. She argues, however, that because defendant made that statement in his capacity as the on-call neurosurgeon, the only conclusion that the jury could reach in this case was that defendant was rendering a diagnosis and either knew or should have known that he was doing so.
In considering the effect of defendant’s on-call status on the analysis, we note, as an initial matter, that the obligations that flow from a physician’s on-call status are not uniform. Compare Hiser v. Randolph, 617 P2d 774 (Ariz Ct App 1980), overruled on other grounds by Thompson v. Sun City Cmty. Hosp., 688 P2d 605 (Ariz 1984) (reversing summary judgment in favor of an on-call doctor who declined to treat a patient because the jury could find that the doctor’s contract with the hospital obligated him to provide care for every person who came to the emergency room),9 with Fought v. Solce, 821 SW2d 218 (Tex App 1991) (upholding summary judgment in favor of an on-call doctor who declined, when asked, to examine an emergency room *282patient because the doctor’s on-call service was voluntary). Those obligations can vary from one institution to the next depending on the institution’s policies, if any; the terms of any agreement to serve as an on-call physician; or, in the absence of institutional policies or an agreement, the customary practice in the relevant medical community.
In this case, neither party identified any hospital policy or agreement between defendant and Legacy that specified defendant’s obligations as an on-call physician. Rather, both parties offered expert testimony on the customary practice in the community. Both Hacker and Kendrick testified that, based on that customary practice, defendant had an obligation as the on-call neurosurgeon to provide care to plaintiff if the emergency room doctor asked him for a consultation or, as Hacker put it, if the emergency room doctor asked defendant to “see” plaintiff. Hacker also testified that, if defendant “had enough information on his own to conclude this is a patient that [he] should see,” then defendant had an obligation as the on-call neurosurgeon to examine or “see” plaintiff and thus enter into a physician-patient relationship with her — a proposition with which plaintiff’s expert agreed.10
As explained above, there was evidence that neither condition occurred in this case. Specifically, the jury could have found that the resident who telephoned defendant on July 1 did not ask him to examine or see plaintiff. Rather, he only asked for defendant’s advice as to whether plaintiff needed to be seen by a neurosurgeon. The jury also could have found that the symptoms that the resident described to defendant depicted a person with a bad back, not someone suffering from cauda equina syndrome. See note 5 above. Finally, the jury could have inferred that those two conditions defined the limits of the obligations that flowed from defendant’s status as the on-call neurosurgeon; that is, the jury could have inferred that, unless one of those two conditions existed, defendant’s status as the on-call *283neurosurgeon had no effect on the question whether his advice gave rise to a physician-patient relationship.
Put differently, neither Hacker nor Kendrick testified that the advice defendant gave on July 1 in his capacity as the on-call neurosurgeon was sufficient, without more, to give rise to a physician-patient relationship. And Hacker offered his expert opinion that no physician-patient relationship arose before July 5, testimony from which the jury could have inferred that defendant’s advice on July 1 was not sufficient, standing alone, to constitute a diagnosis or at least that defendant reasonably should not have known that it was. There is, in short, evidence from which the jury could have inferred that no physician-patient relationship arose as a result of defendant’s advice to the resident.
To be sure, the jury could have drawn a different inference. It could have credited other witnesses and inferred that, in light of defendant’s greater expertise in neurosurgery and the allocation of responsibility between emergency room doctors and on-call physicians, the advice that defendant offered the resident effectively ruled out neurosurgical problems as a cause of plaintiff’s condition and, as a result, defendant should have known that he was rendering a diagnosis on which the resident and others would rely. The jury, however, was not required to draw that inference. It bears repeating that, when a jury has returned a verdict in favor of a party, we must “uphold the jury’s verdict, unless our review of the record reveals that there is no evidence from which the jury could have found the facts” necessary to sustain its verdict. Northwest Natural Gas Co., 333 Or at 310 (emphasis added). There is evidence in this record to support the jury’s verdict.
We note that the conclusion that we reach in this case is consistent with those courts that have considered similar claims. No court has held that an on-call physician’s status coupled with advice about a patient’s condition or treatment establishes, as a matter of law, that an implied physician-patient relationship existed. Rather, the courts have held that the combination of those facts either creates a question of fact for the jury or leads to a ruling, as a matter of law, in favor of the on-call physician. See, e.g., Cogswell v. *284Chapman, 672 NYS2d 460, 462 (NY App Div1998) (where an on-call physician “discussed plaintiff’s injury with [a physician’s assistant treating plaintiff at an emergency room], asked if plaintiff’s eye pressure had been checked, and discussed treatment management with [the physician’s assistant],” an issue of fact existed as to whether the on-call physician’s participation in the patient’s treatment gave rise to a physician-patient relationship); McKinney, 692 NE2d at 1050 (where an on-call cardiologist discussed test results with an emergency room doctor, offered the opinion that the patient’s problems were not cardiac in nature and suggested that the problems could be gastrointestinal, “reasonable minds could come to different conclusions as to whether a physician-patient relationship existed between [the emergency room patient and the on-call cardiologist]”); Schendel v. Hennepin County Med. Ctr., 484 NW2d 803, 808 (Minn CtApp 1992) (where a consulting neurosurgeon countersigned a resident’s report stating that x-rays were negative, protocol required the neurosurgeon to examine the x-ray before countersigning, and the neurosurgeon’s name and telephone number were shown on the outside of the x-ray jacket, “reasonable inferences permitted the jury to conclude that a physician-patient relationship existed between [the neurosurgeon] and [the patient]”).
Indeed, on almost identical facts, the Texas Supreme Court held that no physician-patient relationship existed as a matter of law. See St. John, 901 SW2d at 424. The court reasoned:
“At no time did [the on-call physician] agree to examine or treat [the patient]. Although [the on-call physician] listened to [the treating doctor’s] description of [the patient’s] symptoms, and came to a conclusion about the basis of [the patient’s] condition, he did so for the purpose of evaluating whether he should take the case, not as a diagnosis for a course of treatment.”
Id. Although we question whether the Texas Supreme Court correctly held that no juror could find that the on-call physician in that case had entered into a physician-patient relationship, we agree that a juror could have inferred on those facts (as on these) that no physician-patient relationship existed. The trial court correctly declined to direct a verdict in plaintiff’s favor on the question whether *285defendant entered into a physician-patient relationship with plaintiff on July 1. The Court of Appeals erred in ruling otherwise.
Plaintiff argues alternatively that, even if there were evidence from which the jury could have found that defendant did not enter into a physician-patient relationship with her on July 1, the trial court erred in instructing the jury on that issue. In the Court of Appeals, plaintiff assigned error both to the trial court’s refusal to give her requested instructions and also to the instruction that the trial court gave. We begin with plaintiff’s challenges to the trial court’s instruction.
The trial court instructed the jury:
“In order for [defendant] to be liable for negligence in caring for [plaintiff], he must have had a physician-patient relationship with her. In other words, his actions or failure to act cannot be negligence towards [plaintiff] if she was not his patient when he acted or failed to act.
“If a doctor actually examines a patient, there is a physician-patient relationship.
“Also, if another doctor who is treating a patient calls a specialist, who is on-call, the specialist has a physician-patient relationship with the patient, if,
“(1) the doctor who calls the specialist asks the specialist to see the patient and the specialist does not make it clear to the calling doctor that he or she will not do so or,
“(2) the specialist says he or she will see the patient or,
“(3) the specialist takes some affirmative action to diagnose and/or treat the patient showing an intent to participate in the diagnosis, care or treatment of the patient.
“If a physician is ‘on-call,’ he or she has a duty to be available, to be contacted by emergency room physicians or other health care providers. However, an on-call physician is not automatically in a physician-patient relationship with every patient in the emergency room or the hospital. Also, there is no automatic physician-patient relationship between a specialist and a patient simply because an emergency room doctor or other health care provider calls *286the specialist to talk about the patient, even if the specialist gives general advice.”
At trial, plaintiff objected to the trial court’s proposed instruction on the ground that paragraph (3) includes an erroneous phrase: “showing an intent to participate in the diagnosis, care or treatment of the patient.” Plaintiff argued that she did not “think [a physician] should get a get-out-of-jail-free card by saying I didn’t intend. If he takes affirmative actions that are implicitly indicating that he is participating in the diagnosis, I think you have got it covered.” On review, plaintiff reasserts the objection she raised below. Defendant, for his part, argues that the instruction correctly required the jury to find not only that he undertook to diagnose plaintiff but also that he intended to do so. As we understand defendant’s argument, he contends that a finding of intent is necessary to establish that he impliedly consented to entering into a physician-patient relationship.
The trial court’s instruction required the jury to infer from defendant’s acts “an intent to participate in the diagnosis, care or treatment of the patient.” As explained above, however, it is sufficient if defendant either knew or reasonably should have known that he was diagnosing plaintiff’s condition or providing treatment to plaintiff. In that event, a physician-patient relationship arose and defendant owed a duty of reasonable care to plaintiff. In requiring the jury to find “an intent to participate in the [patient’s] diagnosis, care, or treatment,” the trial court required too much. Defendant does not argue that, if the trial court erred in requiring the jury to find intent, the error was harmless. Such an argument would be difficult to make. An instruction that required proof of intent when a lesser mental state will suffice prejudiced plaintiff. See Wallach v. Allstate Ins. Co., 344 Or 314, 180 P3d 19 (2008) (explaining when instructional error will be prejudicial).11 We accordingly reverse the trial court’s judgment and remand for a new trial.12
*287The decision of the Court of Appeals is affirmed in part and reversed in part. The judgment of the circuit court is reversed, and the case is remanded to the circuit court for further proceedings.
The Court of Appeals decision “ [Reversed [the trial court’s judgment] and remanded for [a] new trial with instructions to provide [a] peremptory instruction to [the] jury on the existence of a physician-patient relationship.” Mead, 231 Or App at 468. Although we agree with the Court of Appeals that the judgment must be reversed and the case remanded for a new trial, we disagree with its direction to give a peremptory instruction on remand. For that reason, we affirm the Court of Appeals decision in part and reverse it in part.
Because the jury found that defendant had not entered into a physician-patient relationship with plaintiff, we state the facts consistently with that finding. See Northwest Natural Gas Co. v. Chase Gardens, Inc., 333 Or 304, 310, 39 P3d 846 (2002) (explaining that, when a jury has returned a verdict in favor of a party, we must “uphold the jury’s verdict, unless our review of the record reveals that there is no evidence from which the jury could have found the facts” necessary to sustain its verdict).
Plaintiff’s claim against Legacy focused on two of its employees — her primary care doctor, Kisor, and an emergency room doctor, Dr. Zigler. (Zigler was not the male resident who had called defendant.) Defendant was not an employee of Legacy, nor was Leonard.
As noted, plaintiff does not dispute that, if a physician-patient relationship did not exist until July 5, she has no claim against defendant.
The jury could have found the following three omissions: First, the resident described the patient’s disk problem as a disk bulge rather than a disk herniation. *274Only the latter poses a risk of cauda equina syndrome. Second, the resident described the patient’s rectal tone as “normal” and did not say that the patient was not able to urinate. An inability to control bowel and urinary functions is a symptom of cauda equina. Third, the resident described the patient as neurologically intact and did not mention weakness or inability to move her lower limbs. Such weakness can signal cauda equina. If the jury credited defendant’s testimony, it could have found that the information he received depicted a person with a bad back who should be treated conservatively and that the patient did not require the services of a neurosurgeon at that time.
The jury also found that defendant had not entered into a physician-patient relationship with plaintiff on July 3, 2002. Because plaintiff has not argued on appeal that the trial court should have directed a verdict on that issue, we have not set out the facts regarding that issue.
An action for medical malpractice “antedated any fully developed theory of negligence as a separate basis for action.” Allan H. McCoid, The Care Required of Medical Practioners, 12 Vand L Rev 549, 551 (1954). The proposition that a physician’s duty extends only to those persons whom he or she agrees to treat derives from cases implying a duty on the physician’s part to “use reasonable and ordinary care and diligence” as an incident of an agreement to provide medical treatment. See, e.g., Leighton v. Sargent, 27 NH 460, 471 (1853) (implying a duty to use due care and diligence as part of a contract to provide medical services to a patient).
One state court of appeals has held that a plaintiff need not prove a physician-patient relationship as a prerequisite to stating a medical malpractice *281claim. Diggs v. Ariz. Cardiologists, Ltd., 8 P3d 386, 389-90 (Ariz Ct App 2000). Having rejected that requirement, it then held, on similar facts, that a specialist owed a duty of care to an emergency room doctor’s patient. Id. at 390. In this case, plaintiff has not argued that we should abandon our cases requiring proof of a physician-patient relationship and follow the approach announced in Diggs.
The court recognized in Hiser that ordinarily “a medical practitioner is free to contract for his services as he sees fit and in the absence of prior contractual obligations, he can refuse to treat a patient, even under emergency situations.” 617 P2d at 776. The court held, however, that a jury could find that the defendant had contracted away that right in return for a daily payment to serve as the on-call emergency room doctor at a local hospital. Id. at 778. That is, the jury could find that, as a result of that contractual obligation, a physician-patient relationship automatically existed between the doctor and the patient whom the doctor refused to see. See id.
Defendant has not argued that some different obligation flowed from his status as an on-call physician, and we assume, for the purpose of analyzing plaintiff’s argument, that Hacker and Kendrick’s testimony accurately described the scope of defendant’s obligations as an on-call neurosurgeon.
Because the issue is likely to arise on remand, we note that the trial court’s instruction appears to track the evidence adduced at trial; that is, it attempts to describe the evidence regarding the practice in the medical community instead of identifying a legal standard and permitting the jury to determine whether the facts, considered in light of the practice in the medical community, met that standard.
As noted, plaintiff also argues that the trial court erred in allowing defendant to ask Leonard and Legacy’s employees whether they were aware that Legacy and *287Leonard had entered into so-called Mary Carter agreements. More specifically, the parties disagreed whether the “rebate” provisions of those agreements were still in effect after the trial court dismissed Legacy and Leonard as defendants and, if not, whether defendant could still seek to impeach the witnesses with the fact that Leonard or Legacy had entered into the agreements. On that issue, plaintiff’s counsel represented that plaintiff, Legacy, and Leonard had modified the agreements after the trial court dismissed Legacy and Leonard as defendants, although plaintiff never submitted the modified agreements to the court. Because this issue may not arise in the same posture on remand, we decline to address it.