TTR and monoclonal gammopathy: The sympathetic skin response and the ESC tests are much better tolerated, but were found to have a much poorer sensitivity, at 33.3% (specificity of 77.6%) and 49.4% (specificity of 92.5%), respectively for various diseases, including familial amyloid neuropathy with TTR mutation, monoclonal gammopathy, primary Sjögren's syndrome, Fabry's disease and autonomic dysfunction of unknown cause20.