Molds contain or produce a variety of biologically active agents such as the cell wall component (1 3)-b-D-glucan, extracellular polysaccharides and mycotoxins. Exposure to molds has been related to airways inflammation, hypersensitivity pneumonitis and reduced resistance to infection. As the exposure under field conditions comprises a multitude of agents, which often covary, it is difficult to attach a specific agent to a specific disease. (1 3)-b-D-glucan has been used as a marker of mold biomass and risk for airways inflammation in studies on indoor environments.