Are there instances where you can defer on mass spectrometry testing for amyloid typing in Congo Red positive tissue?

This is a great question and one that is not uniform in its answer depending on the clinical situation.

Assuming we are talking about at diagnosis here, the short answer is always send Congo red positive bone marrow findings for mass spec typing if there is enough positive protein to dissect and type. Only your pathology colleagues will be able to determine if this is the case, but in bone marrow involvement, there is usually ample material to work with, and I always request it.

We are actually lo...