Confirmatory test for the diagnosis of Amyloidosis is:
Rectal biopsy REF: Robbin's pathology 7th edition page 264 Diagnosis of Amyloidosis depends on demonstration of amyloid deposits in tissue. The most common sites biopsied are the kidney, when renal manifestations are present, or rectal or gingival tissue in patients suspected of having systemic amyloidosis.
Diagnostic peritoneal lavage
Tongue biopsy
Rectal biopsy
Whole body CT scan