Opinion ID: 747742
Heading Depth: 2
Heading Rank: 2

Heading: Reliability of Dr. Gerson's Testimony

Text: 16 The district court refused to admit Dr. Gerson's testimony because of insufficient factual foundation to prove that the cause of Dr. Kannankeril's cognitive impairment was exposure to Dursban. We conclude, however, that Dr. Gerson's opinion meets the requirements for the admission of expert testimony under Rule 702 of the Federal Rules of Evidence, as set forth in Daubert and interpreted by us in Paoli.
17 In its opposition to Dr. Gerson's testimony, Terminix has emphasized that Dr. Gerson did not himself perform any diagnostic medical tests. Terminix argues that Dr. Gerson did not employ sufficient diagnostic techniques to have good grounds for his conclusions or to have properly performed a differential diagnosis. We have recognized differential diagnosis as a technique that involves assessing causation with respect to a particular individual. Paoli, 35 F.3d at 758. Differential diagnosis is defined for physicians as the determination of which of two or more diseases with similar symptoms is the one from which the patient is suffering, by a systematic comparison and contrasting of the clinical findings. STEDMAN'S MEDICAL DICTIONARY 428 (25th ed.1990). 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. See Paoli, 35 F.3d at 759. A differential diagnosis may be reliable with less than all the types of information set out above. See id. Indeed, as we held in Paoli, to the extent that the district court concluded otherwise [i.e., that a differential diagnosis made on less than all types of information cannot be reliable], we hold that it abused its discretion. Id. 18 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. 19 These principles are applicable to the admissibility of Dr. Gerson's expert opinion regarding Dr. Kannankeril. The district court found that Dr. Gerson never performed any clinical tests to support his opinion of causation. Dr. Gerson did not examine, or even speak to Dr. Kannankeril. Instead, Dr. Gerson reviewed the records of Dr. Kannankeril's medical history. Dr. Gerson also relied on Dr. Grober's report of Dr. Kannankeril's neuropsychological complaints and of her cognitive impairment. Terminix does not claim that the medical records relied upon by Dr. Gerson were incomplete or inaccurate. As noted by this Court in Paoli, evaluation 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. Id. at 762. A doctor needs only one reliable source of information showing that a plaintiff is ill; either a physical test or medical records will suffice for this. Id. at 762. For these reasons, the reliability of Dr. Gerson's opinion is not necessarily diminished by the fact that he himself did not perform a physical examination. 20 Moreover, in making his evaluation, Dr. Gerson was aware that one test, the cholinesterase blood test, did not produce abnormal results. The district court noted that the blood test for cholinesterase levels is the most accepted test method for determining exposure to Dursban. However, the cholinesterase test result is but one of the factors considered by Dr. Gerson. Despite the negative results from this test, Dr. Gerson still opined that, as a matter of reasonable medical certainty, Dursban had caused Dr. Kannankeril's cognitive impairment. It is for the jury to decide whether a single cholinesterase test, yielding results within normal limits, outweighs the other factors relied upon by Dr. Gerson and undermines his opinion. This is an issue of credibility, not of admissibility. 21 Furthermore, we do not agree with the trial court's finding that every objective medical test showed normal results. The cholinesterase test was not the only clinical test performed on Dr. Kannankeril. Dr. Grober, the neuropsychologist at the Albert Einstein Medical Center, confirmed a diminution in Dr. Kannankeril's cognitive abilities. 22 In attacking the differential diagnosis performed by the plaintiff's expert, the defendant may point to a plausible cause of the plaintiff's illness other than the defendant's actions. It then becomes necessary for the plaintiff's expert to offer a good explanation as to why his or her conclusion remains reliable. Paoli, 35 F.3d at 762. Dr. Gerson, however, was never challenged by the presentation of alternate diagnoses by other physicians. Moreover, Terminix, in challenging Dr. Gerson's opinion, has not raised any other theory of causation for Dr. Kannankeril's cognitive impairment. 7 The record in this case is devoid of any alternate diagnosis which Dr. Gerson ignored or failed to consider. 23 Furthermore, we reject Terminix's argument that Dr. Gerson admitted to alternate causes other than exposure to Dursban for Dr. Kannankeril's condition. Dr. Gerson had testified at his deposition that something other than exposure to organophosphates could have caused each of the individual symptoms displayed by Dr. Kannankeril. While, however, an alternate explanation for each of Dr. Kannankeril's individual symptoms may exist separately, Dr. Gerson concluded with reasonable medical certainty that Dursban was the most likely cause of her condition as a whole. Terminix's exploration of the cause of each individual symptom goes not to the admissibility of the evidence but to its weight.
24 The Kannankerils also contend that the district erred in finding that Dr. Gerson had no knowledge of Dr. Kannankeril's degree of exposure to Dursban. According to the district court, Dr. Gerson did not know the levels of Dursban at the Kannankerils' home at the time of exposure, and he did not know the amount of time plaintiffs spent in the home. We conclude, however, that the district court erred when it failed to recognize that Dr. Gerson had sufficient knowledge of exposure from his review of Terminix's application records, showing when, how much, and where pesticide had been applied. 25 Terminix asserts, however, that these application records are unreliable as a matter of law as a tool to determine Dr. Kannankeril's exposure. The trial court agreed and ruled that the only information reviewed by Dr. Gerson which addressed actual levels of pesticides in the Kannankeril home was the analysis performed by the DEP in July 1991, nine months after the last application of Dursban. The results of that sampling indicated nondetectable levels of pesticides. 26 We find that Terminix's assertion is without merit. First, there is no expert opinion in the record to establish that an ambient air test, particularly an ambient air test performed nine months after the final application of Dursban, is the only appropriate way in this case to gauge exposure to the organophosphate. Moreover, the plaintiffs were prepared to offer into evidence the Dursban product label which contained warnings such as: HARMFUL IF SWALLOWED. HARMFUL IF ABSORBED THROUGH SKIN. CAUSES EYE AND SKIN IRRITATION and Thoroughly wash dishes and food handling utensils with soap and water if they become contaminated by application of this product. Do not allow children or pets to contact treated surfaces until spray has dried. App. at 241-43. Under the facts as presented in this case, the district judge erred in ruling that an expert may rely only on the ambient air test to determine whether Dr. Kannankeril had been exposed to Dursban. Instead, all factual evidence of the presence of the chemicals in the residence should be relevant in forming an expert opinion of causation. 27 We conclude that it is for the trier of fact to determine what weight to give the ambient air test results as an indication of exposure. See Joiner v. General Elec. Co., 78 F.3d 524, 534 (11th Cir.1996) (reversing exclusion of expert opinions that plaintiffs' exposure to certain chemicals caused his lung cancer where there were issues of fact whether plaintiff was actually exposed to the chemicals so that summary judgment based on a finding of no exposure was inappropriate). The issue whether an ambient air test should be given more weight than pesticide application records goes to the weight rather than the admissibility of evidence. See United States v. Velasquez, 64 F.3d 844, 848 (3d Cir.1995) (citing United States v. Jakobetz, 955 F.2d 786, 800 (2d Cir.1992)). The trial judge must be careful not to mistake credibility questions for admissibility questions.
28 Two other factors that a district court can take into account in assessing reliability are peer-review and publication. They may not, however, in every case be necessary conditions of reliability. See Daubert, 509 U.S. at 593, 113 S.Ct. at 2796-97; Paoli, 35 F.3d at 742. In the instant case, Dr. Gerson admitted that he has not produced any publication on organophosphates. Because the toxic effects of organophosphates on humans are well recognized by the scientific community, however, Dr. Gerson's opinion is not a novel scientific theory regarding organophosphates. 8 Instead, Dr. Gerson merely reported that Dr. Kannankeril exhibited the signs and symptoms of chronic toxicity related to exposure to chlorpyrifos (Dursban). Thus, although Dr. Gerson did not write on the topic, his opinion is supported by widely accepted scientific knowledge of the harmful nature of organophosphates. See also McCullock v. H.B. Fuller Co., 61 F.3d 1038, 1042 (2d Cir.1995) (holding that peer review and publication or general acceptance of an expert's theory goes to the weight of the testimony rather than its admissibility). 29 Based on the record before us, we conclude that Dr. Gerson's opinion on causation has a factual basis and supporting scientific theory. Dr. Gerson based his opinion on Dr. Kannankeril's medical records, Dr. Grober's reports confirming her medical condition, and Terminix's application receipts. He also relied on general experience and readings, general medical knowledge, standard textbooks, and standard references. After considering all the relevant facts, Dr. Gerson reported that [t]he temporal relationship and the nature of her complaints lead me to conclude that with reasonable medical certainty, the cause of Dr. Kannankeril's Central Nervous System manifestations of toxicity is exposure to Dursban in 1989 to 1990. App. at 51. Dr. Gerson's testimony is neither conjecture nor speculation. His opinion was clearly stated to a reasonable degree of medical certainty. 30 Whether the appellants' expert might have done a better job is not the test. We have stated that it is an abuse of discretion to exclude testimony simply because the trial court does not deem the proposed expert to be the best qualified or because the proposed expert does not have the specialization that the court considers most appropriate. Holbrook, 80 F.3d at 782. If the expert meets liberal minimum qualifications, then the level of the expert's expertise goes to credibility and weight, not admissibility. See Paoli, 35 F.3d at 741. The Second Circuit addressed a similar issue and commented that the expert's alleged shortcomings were raised properly on cross-examination and went to the credibility, not the admissibility, of his testimony. McCullock v. H.B. Fuller Co., 61 F.3d 1038, 1043 (2d Cir.1995). Consequently, we reject Terminix's suggestion that Dr. Gerson must be a specialist in Dursban to provide expert testimony on the causation of Dr. Kannankeril's injury. 31 The Kannankerils' burden is only to provide an expert opinion that is relevant and reliable and that will assist the trier of fact. As we have repeated above, issues of credibility arise after the determination of admissibility. Credibility is for the jury. We conclude that, under the facts presented here, the district court erred in ruling that Dr. Gerson's expert testimony on causation was inadmissible.