Difference in potassium permanganate sensitivity between primary and secondary amyloidosis.

The permanganate method was applied to tissues from 35 cases of amyloidosis seen at the University Hospital. Kuala Lumpur. This method is based on the difference in affinity of various chemical types of amyloid for Congo red dye after treatment with potassium permanganate. Our findings agree with the concept that amyloid of largely immunoglobulin light chain composition (primary and myeloma amyloid) is permanganate-resistant while amyloid composed predominantly of AA protein (secondary amyloid) is sensitive. This simple histochemical method is a useful laboratory aid in the classification o famyloidosis.