The best investigation for the diagnosis of amyloidosis is:
Colonoscopy
Rectal biopsy
Upper GI endoscopy
CT scan
The histological examination of the biopsy material is the commonest and confirmatory method for the diagnosis in a suspected case of amyloidosis. The sites for the biopsy can be:- Renal tissue Rectum Abdominal fat aspiration Gingiva. The rectum Q is the best site for taking the biopsy in the options provided. However as per Harrison latest edition, the abdominal fat aspirate is currently the best option for systemic amyloidosis.
Amyloidosis