Samples are first examined with a stereobinocular microscope. Second, the types of asbestos found are indicated.
Many samples consist of distinct materials or layers, which are analyzed separately.
Asbestos results from each layer or material are reported individually. Asbestos fibers may be present in some floor tile samples, or other non-friable materials, but may not be detectable by PLM, due to their small size or to the presence of binding materials. The same considerations also apply to dust samples. Amounts of asbestos below one percent can be detected by routine PLM techniques, but cannot be reliably quantified. TEM analysis, is required for such low levels.