Search results
Congo red stain is the gold standard for the demonstration of amyloid in tissue sections. Used to evaluate the presence and extent of amyloidosis in different organs. Common diseases for Congo red stain include primary amyloidosis, amyloid light chain (AL) seen in plasma cell dyscrasias, amyloid A (AA) associated with inflammatory conditions.
Jan 9, 2022 · The Congo red staining principle is based on the formation of hydrogen bridge bonds with the carbohydrate component of the substrate. Congo red is an anionic dye and is capable of depositing itself in amyloid fibrils, which then exhibit a conspicuous dichroism under polarized light.
Jan 1, 2019 · Staining with Congo Red dye (CR) is one of the major methods used to detect the amyloid structure of protein aggregates. However, a series of experiments have shown that CR staining is insufficient for confirmation of the amyloid nature of protein aggregates.
Congo red is a reactive agent that changes color from red to dark blue in acidic environments where the pH is less than 3. Acid producing mucosa turns blue within a few minutes, whereas non–acid-producing mucosa remains red.
May 31, 2017 · Teaching Points. Importance of the congo red stain. The ability to detect amyloid deposits in human tissue is the critical first step in making a diagnosis of amyloidosis.
Nov 7, 2022 · The tissue diagnosis of amyloidosis is traditionally suggested by hematoxylin-eosin stain and confirmed by Congo red stain, both examined by routine light microscopy. Both false-positive and false-negative congophilia are well documented, limiting the sensitivity and specificity of the Congo red stain for the diagnosis of amyloidosis.
Oct 9, 2019 · Selective congo red staining (congophilia) by amyloid is attributed to formation of non-ionic hydrogen bond between amyloid and dye imparting it deep pink to red color (Fig. 1 b). It is enhanced by alkaline PH and depends on thickness of section. 6–10 µ thick sections are required for optimal staining.
Congo red (CR) is the most popular dye used as a probe for diagnosing amyloidosis, a very heterogeneous group of diseases with more than 23 chemically different amyloid syndromes of men and animals, leading to more than 400 different individual diseases.
Congo red staining is a standard method used to examine ex vivo tissue sections for amyloid fibril deposits. The ex vivo tissue sections are tested for the presence of amyloid by first denaturing native proteins in the tissue sections followed by staining the fibrils with Congo red.
Uniquely in the case of amyloid, Congo red, a fabric dye, has been used for the detection of amyloid deposits since the early 20th century. In contrast, fibrillary deposits in FGN (as well as all other organized deposits) have been shown to be noncongophilic.
