<prompt> Confirmatory test for the diagnosis of Amyloidosis-Diagnostic peritoneal lavageTongue biopsyRectal biopsyWhole body CT scan  <response>: Biopsy and subsequent Congo red staining is the most impoant tool in the diagnosis of amyloidosis. In general, biopsy is taken from the organ suspected to be involved. For example, renal biopsy is useful in the presence of urinary abnormalities. Rectal and gingival biopsy specimens contain amyloid in as many as 75 of cases with generalized amyloidosis Robbins page no. 172 