Residual Reagent Background from Inadequate Washing (Immunohistochemistry (High Background))

Question

Accepted Answer

Elevated background signal caused by residual fixative or unbound antibodies remaining on tissue sections between procedural steps, producing false-positive staining. Common causes: 1) Insufficient washing time between incubation steps 2) Too few wash cycles to remove unbound antibodies 3) Residual fixative remaining in tissue after fixation step 4) Inadequate buffer exchange between procedural steps 5) Unbound primary or secondary antibodies not fully removed Solutions: 1) Increase the washing time for each wash step 2) Increase the number of wash cycles between incubations 3) Wash tissue extensively in buffer between all procedural steps 4) Use fresh buffer for each wash to ensure complete reagent removal 5) Implement agitation during washing to improve reagent clearance