Best investigation for diagnosing amyloidosis ?

Ans. is 'a' i.e., Rectal biopsy Diagnosis of amyloidosis The most definitive investigation for amyloidosis is biopsy. The diagnosis of amyloidosis is made by detecting the characteristic amyloid protein in a biopsy specimen of involved tissue. o For many years rectal biopsy was the first procedure of choice. However, the capillaries in the subcutaneous fat are aften involved in patients with systemic amyloidosis and can often provide sufficient tissues for the diagnosis of amyloidosis. o Therefore, a needle aspiration biopsy of fat just under the skin of the belly (fat pad aspiration) offers a simple and less invasive method to diagnose systemic amyloidosis and biopsy of the organ with the most severe clinical involvement is often unnecessary. o When the subcutaneous fat aspiration biopsy does not provide information to reach a final diagnosis, biopsy samples can be collected from other organs. o The best sites of biopsy are abdominal fat pad (90% sensitivity) and rectal mucosa (70-80% sensitivity). Other sites are salivary glands, gingiva, skin, tongue, bone marrow, stomach.