Congo Red
Use
Congo red stain is a special immunohistochemical procedure used as the gold standard to demonstrate amyloid deposits in tissue sections. It is primarily applied for the diagnosis of amyloidosis, where the amyloid‑fibril–Congo red complex displays characteristic 'apple green' birefringence under polarized light microscopy. When Congo red staining is positive, additional immunohistochemical evaluation for amyloid subtypes—such as amyloid A, amyloid P, and immunoglobulin light chains—is available if clinically indicated.
Special Instructions
This is provided as a special stain under ‘Tech Only’ level of service. Clients are required to perform manual evaluation of glass slides using polarized light to ensure accurate assessment, as NeoGenomics scanning is done under routine light microscopy. For New York State clients, the date and time of collection must be provided. Use of a cold pack during specimen transport is recommended, ensuring it does not directly contact the specimen.
Limitations
Interpretation relies on manual polarized light microscopy; digital scanned images under routine light microscopy may not fully capture the characteristic apple‑green birefringence. Amyloid subtype classification requires additional stains and should be ordered separately if indicated. The test is limited to histological demonstration of amyloid and does not provide molecular or biochemical characterization beyond morphology.
New York Approved
Methodology
Immunoassay (IHC)
Biomarkers
Result Turnaround Time
24 hours
Related Documents
For more information, please review the documents below
Specimen
Tissue (FFPE)
Volume
Not provided
Minimum Volume
Not provided
Collection Instructions
Formalin‑fixed paraffin‑embedded (FFPE) tissue block preferred, or one unbaked unstained slide (4‑5 microns) plus two to three positively charged unstained slides (10 microns). Block and slide identifiers must match requisition.