How is inclusion body myositis (IBM) diagnosed?

Doctors use a muscle biopsy to diagnose IBM. After giving an anesthetic, a doctor takes a sample of tissue from one of the affected muscles to be looked at in a laboratory.

When viewed under the microscope, the muscle cells of persons with IBM contain vacuoles (rounded empty spaces). Within the vacuoles, there are usually abnormal clumps of several proteins including one called amyloid. The protein clumps, or inclusion bodies, give IBM its name. This is the hallmark of IBM.

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