Opinion ID: 1208799
Heading Depth: 1
Heading Rank: 5

Heading: The Testimony of Dr. Gregor

Text: The appellants argue that the circuit court abused its discretion in excluding Dr. Gregor's testimony, because (1) Dr. Gregor is qualified as an expert to render an opinion on the identity and cause of appellant Mr. San Francisco's illness, and (2) Dr. Gregor's opinion is reliable under Daubert/Wilt. As to Dr. Gregor's qualifications as an expert, the appellants assert that Dr. Gregor is a physician board-certified in internal medicine with a sub-specialty in cardiovascular disease. During his time in practice from 1979 until 2002 (some 23 years), Dr. Gregor treated numerous gastrointestinal conditions, including diagnosing and treating multiple patients suffering from foodborne illnesses. The appellants point out that the Gentry Court stated that once an expert passes the minimal threshold, further credentials affect the weight of the testimony not its admissibility.  195 W.Va. at 523 n. 14, 466 S.E.2d at 182 n. 14. The appellants therefore argue that because Dr. Gregor is qualified to diagnose patient illnesses (including foodborne illnesses), diagnose the cause of those illnesses, and then treat patients in a hospital setting, he is similarly qualified to render an opinion on the diagnosis and cause of an illness in a courtroom. The appellee, however, argues that Dr. Gregor does not have a specialization in gastroenterology or epidemiology. Further, Dr. Gregor had never testified in court regarding foodborne illnesses prior to this case, had never conducted research or studies on the topic, and had never worked in the fields of epidemiology or public health.' The appellee cites to Dr. Gregor's own deposition testimony, where he admitted that medical experts in other fields would be better qualified to render an opinion: A. . . . And I'm not an expert in the etiology of foodborne illness, nor do I claim to be one today. Q. Okay. Would you then defer to the opinions of a qualified gastroenterologist or infectious disease expert on those issues regarding etiology? A. As regards to organism? Q. Right. Organism or causation. A. Yes. The appellee argues that, while Dr. Gregor is highly qualified as a board certified cardiologist, he is not a gastroenterologist, infectious disease physician, public health physician, or epidemiologistall of which are medical fields that deal specifically with foodborne illnesses. Accordingly, the appellee asserts that the circuit court was fairly persuaded that Dr. Gregor did not possess the necessary threshold of expertise to testify, and properly was within its discretion in excluding Dr. Gregor's testimony. After careful consideration, we reject the appellee's position because it is directly contrary to Rule 702 and our holding in Gentry. Rule 702 states that a broad range of knowledge, skills, and training qualify an expert as such, and Gentry made clear that we have rejected any notion of imposing overly rigorous requirements of expertise. In Gentry, the Court expressed the concern that there is no best expert rule, and [n]either a degree nor a title is essential, and a person with knowledge or skill borne of practical experience may qualify as an expert. 195 W.Va. at 525 and n. 18, 466 S.E.2d at 184 and n. 18. Therefore, [b]ecause of the `liberal thrust' of the rules pertaining to experts, circuit courts should err on the side of admissibility. Id. The Gentry Court stated plainly that [d]isputes as to the strength of an expert's credentials . . . go to weight and not to the admissibility of their testimony. 195 W.Va. at 527, 466 S.E.2d at 186, citing Daubert, 509 U.S. at 594, 113 S.Ct. 2786 (Vigorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof are the traditional and appropriate means of attacking shaky but admissible evidence.). See also Syllabus Point 3, Walker v. Sharma, ___ W.Va. ___, 655 S.E.2d 775 (2007) ([I]ssues that arise as to the physician's personal use of a specific technique or procedure to which he or she seeks to offer expert testimony go only to the weight to be attached to that testimony and not to its admissibility.) As a physician board-certified in internal medicine, with several decades of experience diagnosing and treating patients with foodborne illnesses, Dr. Gregor meets the minimal educational or experiential qualifications in a field that is relevant to the subject under investigation which will assist the trier of fact. A broad range of knowledge, skills and training qualify Dr. Gregor to offer his opinion regarding the diagnosis and cause of Mr. San Francisco's illness. Furthermore, Dr. Gregor's area of expertise covers the particular opinion as to which he seeks to testify. While a physician with a specialization in gastroenterology or epidemiology might, as the appellee wishes, be better qualified to render an opinion on behalf of the appellants, Gentry and Rule 702 do not impose such overly rigorous requirements of expertise. Gentry, 195 W.Va. at 524-25, 466 S.E.2d at 183-84. While the court may rule that a certain subject of inquiry requires that a member of a given profession, such as a doctor, an engineer, or a chemist, be called, usually a specialist in a particular branch within the profession will not be required.  195 W.Va. at 526, 466 S.E.2d at 185, quoting Charles McCormick, Evidence ¶ 14 at 29 (1954). Accordingly, we conclude that the circuit court erred in excluding Dr. Gregor's testimony on the basis that. Dr. Gregor was not qualified to offer expert testimony under Rule 702. Once an expert is deemed qualified, the trial court must address whether the methodology underlying the expert's conclusion is reliable. The appellants argue that Dr. Gregor's opinion is reliable under the Daubert/Wilt analysis, and that the circuit court erred when it excluded the opinion. The appellants assert that Dr. Gregor's opinion was formed through a scientific method called differential diagnosis. Differential diagnosis involves the determination of which one of two or more diseases or conditions a patient is suffering from, by systematically comparing and contrasting their clinical findings.' McClain v. Metabolife Intern., Inc., 401 F.3d 1233, 1252 (11th Cir.2005) ( quoting Borland's Illustrated Medical Dictionary 240 (Douglas M. Anderson et al. ed., 29th Ed.2000)). Differential diagnosis, or differential etiology, is a standard scientific technique of identifying the cause of a medical problem by eliminating the likely causes until the most probable one is isolated. Westberry v. Gislaved Gummi AB, 178 F.3d 257, 262 (4th Cir.1999). The appellants indicate that Dr. Gregor was on staff at Logan General Hospital on May 3, 2002, and treated Mr. San Francisco in the hospital's emergency room. Dr. Gregor noted his patient's symptoms, particularly noting that Mr. San Francisco vomited 1.8 liters while in the emergency room. After considering his patient's symptoms and history, Dr. Gregor ruled out various likely causes for, the illness after finding no pre-existing gastrointestinal problems, no alcohol use, no peptic ulcer disease and no history of diverticulitis. Dr. Gregor conducted a clinical examination of Mr. San. Francisco, reviewed his medical history, his recent travel history, and his food intake history. Taking all of these factors together, Dr. Gregor eliminated various likely causes and concluded that the most probable cause of Mr. San Francisco's problem was a foodborne illness caused by the allegedly undercooked Wendy's hamburger. When asked why he chose the undercooked hamburger as the cause of plaintiffs illness as opposed to other possibilities, Dr. Gregor explained [i]t's the highest probability of a series of possibilities. The appellee responds by arguing that Dr. Gregor's opinion is still unreliable and inadmissible. While Dr. Gregor might be trained in the process of deducing a disease based on a set of symptoms and laboratory tests, the appellee argues that Dr. Gregor was essentially speculating about the cause of Mr. San Francisco's illness. The appellee suggests in its brief, as a factual matter, that there are more obvious culprits of Mr. San Francisco's illness in the foods that Mr. San Francisco ate [4] and in the people that Mr. San Francisco visited [5] in the week preceding his eating of the Wendy's hamburger. But in answer to the appellants' legal position, the appellee essentially argues that a differential diagnosis of a particular illness does not necessarily result in a relevant and reliable opinion of the cause of the illness. The ability to diagnose medical conditions is not remotely the same, however, as the ability to deduce, delineate, and describe, in a scientifically reliable manner, the causes of those medical conditions. Wynacht v. Beckman Instruments, Inc., 113 F.Supp.2d 1205, 1209 (E.D.Tenn.2000). In general terms, physicians routinely rely upon differential diagnosis for establishing causation. The overwhelming majority of courts that have addressed the issue have held that a medical opinion on causation based upon a reliable differential diagnosis is sufficiently valid to satisfy the reliability prong of the Rule 702 inquiry. Most circuits have held that a reliable differential diagnosis satisfies Daubert and provides a valid foundation for admitting an expert opinion. The circuits reason that a differential diagnosis is a tested methodology, has been subjected to peer review/publication, does not frequently lead to incorrect results, and is generally accepted in the medical community. Turner v. Iowa Fire Equip. Co., 229 F.3d 1202, 1208 (8th Cir.2000). [6] In accord, Heller v. Shaw Indus., Inc., 167 F.3d 146, 154-55 (3rd Cir.1999) (noting that differential diagnosis `consists of a testable hypothesis,' has been peer reviewed, contains standards for controlling its operation, is generally accepted, and is used outside of the judicial context.). Even with all the advances of medical science, the practice of medicine remains an art. A properly conducted and explained differential diagnosis is not junk science. If a differential diagnosis provides a sufficient basis on which to prescribe medical treatment with potential life-or-death consequences, it should be considered reliable enough to assist a fact finder in understanding certain evidence or determining certain fact issues. Coastal Tankships, U.S.A., Inc. v. Anderson, 87 S.W.3d 591, 604-05 (Tex.App.2002). However, while most courts recognize the methodology of differential diagnosis as a scientifically valid way of determining causation, the same courts also warn that opinions based on differential diagnosis must be analyzed on a case-by-case basis, ensuring that the expert's application of the technique is reliable and proper in each case. As the Eleventh Circuit Court of Appeals explained: [A]n expert does not establish the reliability of his techniques or the validity of his conclusions simply by claiming that he performed a differential diagnosis on the patient. . . . No one doubts the utility of medical histories in general or the process by which doctors rule out some known causes of disease in order to finalize a diagnosis. But such general rules must . . . be applied fact-specifically in each, case. McClain v. Metabolite Inc., 401 F.3d at 1253 ( quoting Black v. Food Lion, Inc., 171 F.3d 308, 814 (5th Cir.1999)); see also In re Paoli, 35 F.3d at 758 (Differential diagnosis is a method that involves assessing causation with respect to a particular individual. As a result, the steps a doctor has to take to make that (differential) diagnosis reliable are likely to vary from case to case[.]) Thus, an expert's use of differential diagnosis is reliable and valid only if the expert applied the technique in a manner which is also reliable. A reliable differential diagnosis typically, though not invariably, is performed after physical examinations, the taking of medical histories, and the review of clinical tests, including laboratory tests, and generally is accomplished by determining the possible causes for the patient's symptoms and then eliminating each of these potential causes until reaching one that cannot be ruled out or determining which of those that cannot be excluded is the most likely. Westberry, 178 F.3d at 262 (citation and internal quotation marks omitted). The elements of a differential diagnosis may consist of the performance of physical examinations, the taking of medical histories, and the review of clinical tests, including laboratory tests. A doctor does not have to employ all of these techniques in order for the doctor's diagnosis to be reliable. A differential diagnosis may be reliable with less than all the types of information set out above. . . . Depending on the medical condition at issue and on the clinical information already available, a physician may reach a reliable differential diagnosis without himself performing a physical examination, particularly if there are other examination results available. In fact, it is perfectly acceptable, in arriving at a diagnosis, for a physician to rely on examinations and tests performed by other medical practitioners. Kannankeril v. Terminix Intern., Inc., 128 F.3d at 807. See also In re Paoli, 85 F.3d at 762 ([E]valuation of the patient's medical records is a reliable method of concluding that a patient is ill even in the absence of a physical examination.) A differential diagnosis that fails to take serious account of other potential causes may be so lacking that it cannot provide a reliable basis for an opinion on causation. However, a medical expert's causation conclusion [based on a differential diagnosis] should not be excluded because he or she has failed to rule out every possible cause of a plaintiffs illness. The alternative causes suggested by a defendant affect the weight that the jury should give the expert's testimony and not the admissibility of that testimony. Westberry, 178 F.3d at 265 (citation and internal quotation marks omitted). Differential diagnosis is not a scientific method which lends itself to establishing a direct link between an activity and an illness or injury. Instead, it is a method by which a physician considers all relevant potential causes and then eliminates alternative causes. . . . Federal Judicial Center, Reference Manual on Scientific Evidence 214 (1994). It is a process of elimination based upon a study limited to an evaluation of the patient alone. We therefore conclude that a medical opinion based upon a properly performed differential diagnosis is sufficiently valid to satisfy the reliability prong of the Rule 702 inquiry under Daubert/Wilt. A differential diagnosis is a tested methodology, has been subjected to peer review/publication, does not frequently lead to incorrect results, and is generally accepted in the medical community. Opinions based on differential diagnosis must be analyzed on a case-by-case basis, ensuring that the medical expert's application of the technique is reliable and proper in each case. When Dr. Gregor was questioned regarding his opinion as to causation, and why he chose the undercooked hamburger as the cause of the appellant's illness as opposed to other possibilities, Dr. Gregor explained that [i]t's the highest probability of a series of possibilities. Appellee Wendy's argues that Dr. Gregor's differential diagnosis was unreliable because he failed to definitively rule out all other potential causes for Mr. San Francisco's illness. However, we believe that the alternative causes suggested by the appellee affect the weight that the jury should give the expert's testimony, and not the admissibility of that testimony. See, e.g., McCullock v. H.B. Fuller Co., 61 F.3d 1038, 1044 (2nd Cir.1995) (recognizing that perceived faults in a doctor's differential diagnosis are matters for cross-examination that do not affect admissibility); In re Paoli R.R. Yard PCB Litig., 35 F.3d at 764-65 (recognizing that failure to account for all possible causes does not render expert opinion based on differential diagnosis inadmissible; only if the expert utterly fails to consider alternative causes or fails to explain why the opinion remains sound in light of alternative causes suggested by the opposing party is the expert's opinion unreliable for failure to account for all potential causes). We therefore conclude that, under a Daubert/Wilt analysis, Dr. Gregor's differential diagnosis of the cause of Mr. San Francisco's illness is reliable and admissible. C.