Global patterns of amyloid typing: results of a survey by the International Society of Amyloidosis (ISA)

Accurate tissue typing in amyloidosis is essential to provide appropriate therapy for individual patients. To get a real-life overview of typing strategies worldwide. The International Society of Amyloidosis (ISA) performed an online questionnaire survey among ISA members. We prepared questionnaire sheets for referral institutions (Category 1; C1), institutions performing amyloid typing for internal requests only (C2), and institutions outsourcing amyloid typing to referral institutions (C3), respectively. Seventy-six institutions participated in this survey, including C1 (<i>n</i> = 33), C2 (<i>n</i> = 20) and C3 (<i>n</i> = 23) institutions. Multiple typing methods were available across the responding institutions, including immunohistochemistry (85% of C1/C2 institutions), immunofluorescence microscopy (43%), genetic analysis (77%) and mass spectrometric analysis (42%). Commercial antibodies were used worldwide for immunohistochemistry. C1 institutions in Europe and Asia also used various in-house antibodies. Ninety-three percent of institutions performed genetic analysis of <i>TTR gene</i>, followed by <i>APOA1</i> (43%), <i>FGA</i>, <i>GSN</i>, <i>LYZ</i> (33%) and <i>APOA2</i> (31%). Hierarchical referral flows of mass spectrometric analysis, immunohistochemistry and genetic analysis were observed regionally and internationally. Globalization and centralization of referral flows were more prominent for mass spectrometric analysis. These data provide an assessment of the current state, enabling improvement in capabilities of amyloid typing worldwide and enhancing regional/international networks.