Amyloidosis can only be diagnosed by a positive biopsy; that is, an identification of the amyloid deposits in a piece of tissue. Tissue biopsies must be stained properly with Congo red, a dye which will color the amyloid if it is present and cause it to have a unique appearance when viewed under a special microscope.
If amyloid is present in a tissue biopsy, further tests can be done in the research laboratory to help determine the type of the amyloid. Initial biopsies are most commonly obtained from the abdominal fat. If amyloid is suspected in other organs, however, a biopsy may be needed from these specific areas.
Before a patient arrives at Boston University’s Amyloid Program, they are requested to have the slides from a positive biopsy sent so that we may confirm the diagnosis of amyloidosis. Two unstained slides from the biopsy will be requested, as well as one slide that has been stained with Congo red.
For reasons noted above, it is important that the stained slides sent to the Program are Congo red and not another stain. The receipt of inappropriate slides may cause a delay in evaluation.