Congo Red and amyloids: history and relationship.

Staining with Congo Red (CR) is a qualitative method used for the identification of amyloids and in tissue sections. However, the drawbacks and artefacts obtained when using this dye can be found both and Analysis of scientific data from previous studies shows that CR staining alone is not sufficient for confirmation of the amyloid nature of protein aggregates or for diagnosis of amyloidosis in tissue sections. In the present paper, we describe the characteristics and limitations of other methods used for amyloid studies. Our historical review on the use of CR staining for amyloid studies may provide insight into the pitfalls and caveats related to this technique for researchers considering using this dye.