The opinion of the court was delivered by: Ellen Segal Huvelle United States District Judge
MEMORANDUM OPINION AND ORDER
Plaintiffs Denicole Young and Vanessa Ghee have sued William F. Burton and Lewis & Tompkins, P.C., for legal malpractice based on their failure to file a timely personal injury lawsuit. The original lawsuit would have sought recovery for damages suffered by plaintiffs as a result of exposure to toxic mold while residing at the Stanton Glen Apartments. In order to succeed on their legal malpractice claim, plaintiffs must show that their attorneys' alleged negligence adversely affected their ability to benefit from an otherwise meritorious claim. See Niosi v. Aiello, 69 A.2d 57, 60 (D.C. 1949). To make their case, plaintiffs rely on the testimony of Dr. Ritchie Shoemaker as to the cause, nature, and extent of their injuries. Defendants have moved to exclude Dr. Shoemaker's testimony, arguing that his opinions are not based on a reliable methodology, and that regardless, Dr. Shoemaker did not follow his own methodology with respect to plaintiffs.
Based on the record herein, including the testimony presented at a Daubert hearing, the Court concludes that Dr. Ritchie Shoemaker's diagnosis of plaintiffs, as well as his opinions relating to general and specific causation, are not sufficiently grounded in scientifically valid principles and methods to satisfy Daubert. Therefore, defendants' motion will be granted.
Plaintiffs moved into Apartment 2A at 3064 Stanton Road, S.E. on August 19, 2002. (Compl. ¶ 8.) They resided there for approximately thirty-four days, during which time plaintiffs contend they could smell noxious fumes from raw sewage. (Pls.' Opp'n at 5; Pls.' Ex. 5 [Ghee Dep.] at 252.) In early September 2002, while investigating the smell, plaintiffs climbed through a window of the adjacent apartment, Apartment 1A, and took photographs of the extensive visible mold growth in this vacant apartment. (Defs.' Mot. at 2; Defs.' Ex. 3 [Young Dep.] at 175-78; Pls.' Ex. 7 [Photographs].) Although plaintiffs are not sure exactly how long they spent in Apartment 1A, they estimate it was no longer than one or two minutes. (Defs.' Mot. at 2; Defs.' Ex. 3 at 178.) There was no documentation of any visible mold growth in plaintiffs' apartment (Daubert Hr'g Tr. ["Tr."] at 76:2-5, June 16, 2008), and plaintiffs do not believe the two apartments shared a common air source. (Defs.' Mot. at 2; Defs.' Ex. 1 [Ghee Dep.] at 452). On September 23, 2002, plaintiffs signed a lease agreement for a different unit in the apartment complex and immediately moved into the new apartment. (Pls.' Opp'n at 5; Defs.' Ex. 2 [Lease Agreement].)
Both plaintiffs submitted extensive medical records to document the health problems that they attribute to their mold exposure. Approximately two weeks after moving into the apartment, Vanessa Ghee visited George Washington University Hospital ("GWUH") on September 6, 2002. (Defs.' Ex. 4 [Ghee Medical Records] at 19.) She complained of a productive cough that had lasted three weeks and indicated that she had experienced a similar cough three months prior to that visit. (Id.) She was diagnosed with viral bronchitis and was instructed to use a humidifier at home and to quit smoking. (Id. at 22.) When she returned to GWUH a week later on September 13, 2002, she was given Claritin and again instructed to stop smoking. (Id. at 27.) After moving out of the apartment, Ghee required medical care only intermittently. (Pls.' Ex. 11 [Ghee Medical Records].)
Denicole Young's medical records indicate significant medical problems prior to moving into the apartment. She was seen for bronchitis and sinusitis as early as December 10, 1996. (Defs.' Ex. 5 [Young Medical Records] at 642.) She was seen again for sinus congestion and cough on October 21, 1997 (id. at 632) and July 29, 1998 (id. at 609), and she complained of chronic fatigue on January 9, 1998 (id. at 611) and March 10, 2000. (Id. at 602). She was also seen many times during those years for complications from her sickle cell trait. Young went to GWUH with Ghee on September 6 and 13, 2002, and was also diagnosed with bronchitis, prescribed Claritin, and told to use her inhaler. (Defs.' Ex. 5 at 656-59.) Young's medical records from the September 13 visit indicate a past history of asthma (id.), although it is unclear exactly when she first received that diagnosis. In the months after moving out of the apartment, Young required a few medical visits for minor problems but was hospitalized for asthma exacerbation and pneumonia on April 15, 2003. She required intubation on three separate occasions during that hospital stay. (Pls.' Ex. 12 [Young Medical Records] at 983-94.) She had regular doctors' visits over the next two years relating to asthma, sore throats, coughing, allergic reactions, and swelling in her extremities. (Id. at 157-52, 150-48, 145-38, 134-33, 131-27, 123- 22, 118-16, 84-80, 75-74, 971-82, 924-35, 912-23, 899-911, 1000-22, 1055-70, 1086-94, 1308-13, 1326-30, 1332-38.)
Dr. Shoemaker received his doctorate from Duke University. (Pls.' Ex. 15 [Shoemaker CV] at 1.) He is currently a member of the American Medical Association, the American Society for Microbiology, the American Society of Tropical Medicine and Hygiene, the International Association for Chronic Fatigue Syndrome, and the Maryland Medical Chirurgical Association. (Id.) He has practiced as a licensed medical doctor in Pocomoke, Maryland since 1980 (Pls.' Ex. 14 [Shoemaker Aff.] ¶ 3) and has been the treating physician for over 4,700 patients whom he has diagnosed with ailments caused by exposure to water-damaged buildings. (Id. ¶ 5). He has also authored numerous publications and books, including Mold Warriors, which was published in 2005. (Id.)
Dr. Shoemaker described his methodology for diagnosing cases of mold illness*fn1 as follows. He begins by following standard diagnostic procedures with new patients: first, he takes the patient's history, and second, he performs an examination of the area that is the subject of the patient's complaint. (Pls.' Ex. 14 ¶¶ 13-14.) Then, depending on the circumstances of the illness and if there is a temporal relationship that suggests that the patient was in a location where he may have been exposed to a possible environmental contaminant, Dr. Shoemaker will turn to his own differential diagnostic procedure for mold illness. (Id. ¶ 15.)
That procedure involves a two-tiered analysis. (Id. ¶ 17.) To satisfy the first tier, all three of the following factors must be met: "(1) the potential for exposure; (2) the presence of a distinctive group of symptoms; and (3) the absence of confounding diagnoses and exposures." (Id. ¶ 18.) According to Dr. Shoemaker, the second tier acts as confirmation of the diagnosis arrived at in the first tier and requires that three of the following six factors be met: (1) HLA DR showing susceptibility to mold illness; (2) reduced levels of melanocyte stimulating hormone (MSH); (3) elevated levels of matrix metalloproteinase-9 (MMP9); (4) deficits in visual contrast sensitivity (VCS); (5) dysregulation of ACTH and cortisol; and (6) dysregulation of ADH and osmolality. (Defs.' Mot. at 6-7.) HLA DR refers to certain genes which Dr. Shoemaker believes are associated with a patient's susceptibility to mold illness. He claims there are certain versions of those genes, or genotypes, which render a patient more likely to have adverse health consequences from exposure to damp indoor environments. (Pls.' Ex. 14 ¶ 21.) VCS is a test of a patient's ability to detect certain visual patterns, which, in turn, is an indicator of neurologic functioning. (Id. ¶ 26.) The other four tests look at levels of certain hormones and enzymes in the blood which Dr. Shoemaker believes are altered by exposure to a biotoxin. (Id. ¶¶ 18-19.) Dr. Shoemaker refers to those hormones and enzymes as "biomarkers."
If a patient meets both tiers of this case definition, Dr. Shoemaker typically recommends treatment with Cholestyramine ("CSM"), a cholesterol-lowering drug which binds molecules in the intestinal track and prevents them from being absorbed into the body. (Defs.' Ex. 7 [Dr. S. Michael Phillips' Report] at 16.) Dr. Shoemaker uses CSM on an off-label basis, meaning he uses it for a purpose other than that for which it has been approved by the FDA. (Id. at 17.)
Dr. Shoemaker has published three peer-reviewed publications regarding mold illness. (Pls.' Ex. 16 [Shoemaker Mold Publications].) The first of these papers established the case definition for biotoxin illness by confirming a set of diagnostic criteria that was present in nearly all of the "cases" of biotoxin illness, and in virtually none of the "control" subjects. Ritchie C. Shoemaker, et al., Sick Building Syndrome in Water Damaged Buildings: Generalization of the Chronic Biotoxin-Associated Illness Paradigm to Indoor Toxigenic Fungi, in BIOAEROSOLS, FUNGI, BACTERIA, MYCOTOXINS AND HUMAN HEALTH: PATHOPHYSIOLOGY, CLINICALEFFECTS, EXPOSUREASSESSMENT, PREVENTION AND CONTROL IN INDOOR ENVIRONMENTS AND WORK, 66- 77 (Eckhardt Johanning, ed., 2005). The second paper looked more closely at the changes in levels of certain biomarkers in biotoxin illness patients in response to treatment and re-exposure. Ritchie C. Shoemaker & Dennis E. House, A Time-Series Study of Sick Building Syndrome: Chronic, Biotoxin-Associated Illness from Exposure to Water-Damaged Buildings, 27(1) NEUROTOXICOLOGY AND TERATOLOGY 29 (2005). The third paper consisted of a double-blind, placebo-controlled study of the use of CSM to treat biotoxin illness and also reaffirmed his case definition. Ritchie C. Shoemaker & Dennis E. House, Sick Building Syndrome (SBS) and Exposure to Water-Damaged Buildings: Time Series Study, Clinical Trial and Mechanisms, 28(5) NEUROTOXICOLOGY AND TERATOLOGY 573 (2006). This third study was extremely limited; it looked at twenty-six subjects, only thirteen of whom participated in the placebo-controlled trial, and each subject served as his own control. Id. at 575-76.
In his studies, Dr. Shoemaker uses a five-step, repetitive exposure protocol to establish the cause of his subjects' illnesses. First, the patient is evaluated under the two tiers explained above and then diagnosed with mold illness. Second, the patient is treated with CSM and tested to ensure that the biomarker levels have returned to normal. Third, the patient stops CSM treatment and stays away from the suspected mold environment to see if the illness returns when exposed to the variety of biotoxins which are ubiquitous in everyday life. If the patient's biomarker levels remain normal, this means that other exposures are ruled out as the source of the symptoms. Fourth, the patient then returns to the mold environment for no more than three days, and finally, the patient is re-tested to obtain final biomarker readings after having re-acquired the illness. (Pls.' Ex. 55 at 31-32.) By demonstrating that the abnormal levels of biomarkers are associated with the patient's presence in the suspected mold environment, Dr. Shoemaker claims that the illness was caused by exposure to that building.
B. Diagnosis of Plaintiffs
Plaintiffs visited Dr. Shoemaker on September 11, 2007, to obtain his expert opinion regarding the etiology of their symptoms. (Pls.' Ex. 55 at 1.) He spent roughly two hours with each plaintiff, during which time he took their medical histories and performed physical exams. (Pls.' Ex. 55 at 14.) He also performed a VCS test, pulmonary function, electrocardiogram, and pulse oximetry.*fn2 (Id.) At that time, he ordered that laboratory tests be conducted on plaintiffs' blood samples to determine plaintiffs' levels of the Tier 2 biomarkers. (Id.) However, even before he received the results of these tests, and thus with no information as to whether plaintiffs met the second tier of his diagnostic criteria, he concluded that "[b]oth Ms. Young and Ms. Ghee acquired a typical biotoxin-associated illness following exposure and re-exposure to the indoor air environment of their townhouse at Apt 2A 3064 Stanton Rd SE, Washington, DC." (Id. at 1.) The September 2007 visit, which occurred five years after plaintiffs moved out of Apartment 2A, was the only time Dr. Shoemaker examined the plaintiffs. At some point after that examination, Dr. Shoemaker received the results of plaintiffs' blood tests, which he believes confirms his initial diagnosis. According to Dr. Shoemaker, Young had four of six abnormal blood test results, and Ghee had three of six (three being the minimum required to meet the second tier). (Pls.' Ex. 14 ¶¶ 103-04.) Both plaintiffs had mold susceptible HLA DR genotypes, and both had deficits in their VCS scores, although Dr. Shoemaker was unable to provide plaintiffs' actual results for the VCS test. (Id.; Tr. at 157:5.) In addition to those tests, Young's tests revealed MSH of 12 pg/ml and MMP9 of 565, and Ghee's test results revealed MSH of 18 pg/ml, all of which Dr. Shoemaker classifies as abnormal. (Pls.' Ex. 14 ¶¶ 103-04.)
Dr. Shoemaker did not perform his five-step protocol on plaintiffs, and indeed could not possibly have done so, as he first met them long after they left the suspected mold environment. Nor was he able to base his causation opinion on the plaintiffs' response to treatment, for both plaintiffs chose not to take the CSM that he had prescribed for them. (Tr. at 19:20-23.) However, he is of the opinion that now that he has proven the research model for mold illness in his 2006 publication, it is no longer necessary to follow the five-step protocol with new patients, because causation necessarily follows from his diagnosis. (Pls.' Ex. 14 ¶ 93.)
At the conclusion of discovery, defendants moved for a Daubert hearing, relying on the affidavits of two experts. According to their expert toxicologist, Dr. Scott Phillips, since there was no evidence as to the exact substance plaintiffs were exposed to or the level at which they were exposed, formal toxicological causation analysis could not be performed. (Defs.' Ex. 6 [Dr. Scott Phillips' Report] at 23-24.) In addition, the tests Dr. Shoemaker uses to reach his diagnosis are experimental and "not generally accepted in the toxicology community." (Id. at 28-29.) Dr. Phillips explained the traditional causation analysis, comprised of the nine "Hill Criteria" that are necessary to establish a causal relationship between two things,*fn3 and using these criteria, he opined that "there is no support for a causal association between the dark material on the adjacent apartment walls and the Plaintiffs['] health complaints." (Id. at 25-26.) Defendants' expert immunologist, Dr. S. Michael Phillips, walked through each of the Hill Criteria and explained how the facts of this case cannot support a finding of causation. (Defs.' Ex. 7 [Dr. S. Michael Phillips' Report] at 10-14.) He also faulted Dr. Shoemaker's conclusions on the grounds that "[b]iotoxins do not cause the spectrum of disease shown by Denicole and Vanessa"; that none of the laboratory criteria Dr. Shoemaker uses to arrive at his diagnosis has been "causally associated with specific biotoxin associated human illness"; and that "the medical community does not recognize" biotoxin-associated illness. (Id. at 15-17.) Also, according to Dr. Phillips, no actual exposure to mold has been demonstrated; neither plaintiff has any symptoms or test results that could be caused by biotoxins; and "allergies and infections may be plausible explanations of Denicole's major respiratory exacerbation" on April 15, 2003. (Id. at 17-18.)
In their opposition, plaintiffs argue that defendants' criticisms only amount to an attack on Dr. Shoemaker's conclusions, not his methodology, and therefore, defendants cannot prevail even if Dr. Shoemaker "draws conclusions from test methods and lab tests established for other purposes, and applies them to a different use." (Pls.' Opp'n at 27.) In making this argument, plaintiffs rely on Dr. Shoemaker's affidavit, in which he elaborated on his methodology and explained that he uses standard differential diagnostic procedures which are widely used and accepted in the scientific community. (Pls.' Ex. 14 ¶¶ 11-16.) Plaintiffs also submitted Dr. Shoemaker's peer-reviewed publications on "mold illness," along with numerous scientific papers explaining the human health effects of mold, in order to rebut defendants' contention that Dr. Shoemaker's testimony is not based on a scientifically valid methodology. (Pls.' Exs. 16-33.)
The Court granted a Daubert hearing, and both parties submitted direct testimony in the form of affidavits from their experts in advance of the hearing. During the hearing, held on June 16, 2008, Dr. Shoemaker was subjected to cross-examination, followed by the testimony of Dr. S. Michael Phillips. Based on this testimony, as well as the parties' prior submissions, the Court makes the following findings of fact and conclusions of law.
I. GOVERNING LEGAL STANDARDS
The admissibility of expert testimony in federal courts is governed by Federal Rule of Evidence 702, which provides:
If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert . . . may testify thereto in the form of an opinion or otherwise.
As explained by the Supreme Court, under Rule 702, "the trial judge must determine at the outset . . . whether the expert is proposing to testify to (1) scientific knowledge that (2) will assist the trier of fact to understand or determine a fact in issue." Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 592 (1993). The first prong of the analysis "establishes a standard of ...