Amyloidosis is a rare condition where insoluble proteins produced in the bone marrow called "amyloids" collect in various organs. However, several diseases feature amyloid depositions (e.g. Alzheimer's, rheumatoid arthritis and dozens more). Therefore, the testing process begins with a blood and urine test to screen for amyloids associated with specific diseases. If these markers aren't found, your doctor will order a biopsy--the only way to officially diagnose amyloidosis.

Blood and Urine Tests

Before prescribing a tissue biopsy, your doctor may first order a blood or urine test in order to rule out certain conditions. Commonly screened for proteins are beta amyloid (Alzheimer's Disease), amylin (Type II Diabetes), serum amyloid A (rheumatoid arthritis) and atrial natriuretic factor (cardiac arrhythmia). If none of these are found, biopsies will be ordered so that the doctor can investigate other possible conditions. Note: if unidentified amyloids are discovered in the urine, the doctor will probably order a kidney biopsy.

Biopsy

Literally speaking, the term "biopsy" refers to a procedure where tissue is taken from a patient and then examined in a laboratory by a specialist. What your amyloidosis biopsy will consist of, however, can vary greatly depending on the number and type of tissue being sampled. Based on the results of your urine test and your observed symptoms, an MRI (magnetic resonance imaging) will be taken of the appropriate organs to look for amyloid accumulation zones. Using the MRI images as guides, a technician will remove tissue samples from the afflicted areas. Certain types of biopsies are minimally invasive, consisting of a locally-applied anesthetic and the insertion of a long needle. For biopsies of cardiac, liver, spleen and nervous tissue, obtaining the sample requires minor surgery and a brief hospital stay. Once the samples have all been obtained, they are dissected, stained and viewed under a powerful microscope by specialists. Based on their findings, they will declare whether or not you have amyloidosis.

Source:

Amyloidosis: Tests And Diagnosis

Amyloids and Alzheimer's Disease