OBJECTIVETo analyze the effect of special staining and immunohistochemical staining in distinguishing the types of renal amyloidosis to improve the diagnosis accuracy.

METHODSCongo red staining with different methods, and immunohistochemical staining of Kappa, Lambda and Amyloid A with different antigen retrieval methods were used for staining frozen and paraffin-embedded renal tissue sections.

RESULTSWright's Congo red staining produced a better contrast and a higher resolution and showed a greater stability than the other 2 methods after repeated use for staining the renal tissue sections (P<0.05). Immunofluorescent staining produced better results in frozen renal tissue sections than in paraffin-embedded tissues. Immunofluorescent staining produced had better performance than immunohistochemical staining in paraffin-embedded tissues. The retrieval effect with protein kinase K was the best among the antigen retrieval methods in paraffin-embedded tissues.

CONCLUSIONWright's Congo red staining is better than the other 2 methods in diagnosing renal amyloidosis. Immunohistochemical staining of Kappa, Lambda and Amyloid A in frozen renal tissue sections is necessary to discriminate the types of renal amyloidosis. For paraffin-embedded renal tissues, antigen retrieval using protein kinase K is better than the other 2 methods.