I am a 67 year old woman recently diagnosed with MM. My oncologist also strongly suspects I have cardiac AL Amyloidosis. Both the bone marrow biopsy and the fat pad biopsy were negative for amyloid, but now he has scheduled a 90 minute cardiac MRI and if that is inconclusive, he wants a cardiac biopsy. Are false negatives common with amyloidosis? Has anyone else been put through this? With two negative tests already, I question the need for further testing. Thanks.