Workup of Amyloidosis

New treatments are available for systemic amyloidosis that contribute to an improved quality of life and even potential cure for patients; however, there is variability and inconsistency among pathologists and laboratories in their approach to amyloidosis workup and diagnosis.

The primary goal of this guideline is to provide evidence-based recommendations on appropriate testing for amyloidosis and the proper evaluation of amyloid positive specimens for subtyping the specific amyloidogenic protein.

1. In patients with suspected systemic amyloidosis (amyloid transthyretin protein [ATTR], amyloid serum A protein [AA], and amyloid light chain [AL]), does fat pad aspiration/biopsy, salivary gland biopsy, and rectal biopsy all provide adequate diagnostic sensitivity?
2. When screening fat pad biopsies for amyloidosis, can cytology samples be used as an alternative to surgical pathology samples (formalin-fixed paraffin-embedded [FFPE] blocks)?
3. In patients with suspected amyloidosis, what method most accurately and reproducibly detects amyloid?
4. When using Congo red stain on slides from patients with suspected amyloidosis, does the addition of fluorescence microscopy to polarized light microscopy provide increased sensitivity and reproducibility for the detection of amyloid?
5. When performing protein subtyping on a case with confirmed amyloid deposition in a paraffin block, what is the diagnostic accuracy of immunohistochemistry when compared with mass spectrometry, and is this dependent on amyloidosis type or biopsy site?
6. When performing protein subtyping on a case with a confirmed amyloid deposition in frozen tissue (i.e. renal, cardiac biopsy), what is the diagnostic accuracy of immunofluorescence when compared with mass spectrometry?

• Guideline status: Research and Review

Sheldon Pinsker

PROSPERO Listing

Review more upcoming CAP evidence-based guidelines by the Center.