The diagnosis of amyloidosis is confirmed by the presence of amyloid deposition in tissue biopsy specimen. A skin punch biopsy from the lesion is the preferred confirmatory procedure. The next best choice is needle biopsy from the abdominal subcutaneous fat from the clinically normal-appearing skin may be performed. The skin and abdominal fat biopsy provide positivity in 86% to 95% of amyloidosis cases, depending upon the type of amyloidosis.In case of clinical suspicion, congo red staining of abdominal fat or other tissue is advised.Ref: Harrison&;s Principles of Internal Medicine; 19th edition; Chapter 137 Amyloidosis; Page no: 720