The sine qua non for the diagnosis of amyloidosis is a tissue biopsy staining positive with Congo red and demonstrating apple-green birefringence under polarized light microscopy. Electron microscopy will also show a classical fibrillar appearance in the extracellular matrix.
It is important to avoid over-staining the tissue with Congo red as this may give false results. The technique of subcutaneous fat pad aspiration offers a simple and relatively non-invasive approach to the diagnosis of systemic amyloidosis and is positive in 70-80 % of patients with systemic amyloidosis. If the fat is negative, but suspicion of disease is high, a biopsy of an involved organ system (e.g., heart, kidney, or liver) may need to be done to make the diagnosis. An involved organ is positive nearly 100% of the time.
Before a patient is evaluated at our treatment and research center, we request of review of the slides and, wherever possible, an unstained block of tissue so that a standardized appropriate stain can be done. Tissues and slides will be returned after evaluation.
Address for sending biopsy material preliminary to a patient evaluation, biopsy material for a second opinion, or blood samples for familial amyloidosis testing. We ask that you call to discuss testing requests before sending samples.
The Amyloidosis Center
Boston University School of Medicine
72 East Concord Street, K-503
Boston, MA 02118