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Maryland Court Of Appeals Affirms Exclusion of “Differential Diagnosis” In Mold Exposure Claims

The Maryland Court of Appeals has affirmed a decsion of the Court of Special Appeals ruling that certain expert testimony is not admissible to support medical clams arising from exposure to mold and other environmental byproducts of damp buildings.  Such claims are often supported by a medical analysis known as “differential diagnosis” and sometimes referred to as “repetitive exposure protocol,” which as been used by physicians to attribute various medical symptoms to inhalation of mold in water-damaged buildings.  Rather than demonstrating a specific exposure to a specific mold resulting in a specific reaction,  differential diagnosis uses a process that “rules out” or “rules in” possible causes of symptoms a patient is experiencing to determine that their symptoms are related to exposure to mold.  Differential diagnosis has been frequently used to show an association between exposure to mold in wet buildings and certain human health effects.  In its opinion in the case of Montgomery Mutual Insurance Co. v. Chesson, the Maryland Court of Special Appeals held that this method is not sufficiently accepted in the scientific community so as to be used as a basis for medical testimony in mold cases.  The Court of Special Appeals reversed a trial court ruling that found such medical testimony to be reliable and admissible.  Maryland’s highest court, the Court of Appeals, has now affirmed the Court of Special Appeals decision.  Chesson v. Montgomery Mutual Insurance Co., Case No. 97, Sept. Term 2012.

The Court of Appeals expressly held that such medical theories are not generally accepted as reliable in the scientifc community, and, therefore, do not meet the Maryland criteria for the admissibility of scientifc evidence as established in Reed v. State, 283 Md. 374 (1978) and Frye v. United States, 293 F. 1013 (1923), which has become known in Maryland as the Frye-Reed standard.  The Court further concluded that, in fact, the scientific community is uncertain as to the techniques and conclusions of the practitioner of differenetial diagnosis in this case.

Mold exposure in damp buildings has become an increasing subject of litigation over the last decade. Much of the litigation involves damage to building components as a result of microbial growth, and the protocols that are required for its safe removal, which arises primarily from the recognition that molds are allergins that can effect the heath of certain individuals.  It is widely recognized that susceptible building occupants can experience various allergic-type symptoms when exposed to damp building conditions, and individuals with pre-existing respiratory conditiions or immune dificiencies can sometime develop respiratory disease.  However, while the need to take specific precautions when dealing with mold contamination is accepted,  litigation related to medical illness has been controversial due to the difficulties of establishing a causal connection between the symptoms and the exposure.  The Maryland Court of Appeals has now determined that, in Maryland, such a connection cannot be established through the use of differential diagnosis techniques.