Weak or absent signal from inadequate antibody concentration or incubation (Immunohistochemistry (No Staining))

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Accepted Answer

No detectable staining despite proper protocol execution. Insufficient antibody-antigen binding due to suboptimal concentration or incubation conditions. Common causes: 1) Primary antibody concentration too low for detection threshold 2) Insufficient incubation time preventing adequate antibody-antigen binding 3) Low-abundance target protein requiring signal amplification 4) Suboptimal incubation temperature reducing binding efficiency Solutions: 1) Increase primary antibody concentration in dilution buffer 2) Extend incubation time (e.g. overnight incubation at 4°C) 3) Use signal amplification methods (biotin-conjugated secondary antibody with streptavidin detection) 4) Optimize antibody concentration by titration (test range 1:50 to 1:500) 5) For low-abundance proteins, use tyramide signal amplification (TSA) systems