Evaluation of a modified Rit Scarlet No. 5 stain for detection of amyloid

We describe a modification of a method of a staining protocol using Rit Sca rlet No. 5 stain for staining a relatively wide spectrum of cases of amyloi dosis that included renal biopsy, synovium of hand, intervertebral disc mat erial, brain tissue, heart, pleura, colon, and thyroid. The modified stain employs a stable, alkaline, alcoholic solution and does not require a diffe rentiation step. The stock Rit Scarlet No. 5 stain need not be prepared fre shly nor require filtration before use. The Rit stain is far more cost effe ctive than Congo red as 100 gm costs about $4.40 in contrast to about $17.0 0 for the same volume of Congo red. The stain can be employed as a convenie nt, rapid and sensitive means to detect amyloid.