Sources | Solutions |
Inadequate deparaffinization | Deparaffinize sections longer or change fresh xylene |
Inactive primary antibodies | Replace with a new batch of antibodies |
Antibodies do not work due to improper storage | Aliquot antibodies into smaller volumes and store in freezer (-20 to -70 C) and avoid repeated freeze and thaw cycles. Or store antibodies according to manufacture's instructions. |
Antibody concentration was too low | Increase the concentration of primary and/or secondary antibodies. Or run a serial dilution test to determine the optimal dilution that gives the best signal to noise ratio |
Inadequate antibody incubation time | Increase antiobody incubation time |
Inadequate or improper tissue fixation | Increase duration of postfixation or try different fixatives |
Tissue overfixation | Reduce the duration of postfixation. If the tissue has already been overfixed, perform an appropriate or recommended antigen retrieval procedure. |
Incompatible secondary and primary antibodies | Use secondary antibody that will interact with primary antibody. For example, if primary antibodies are raised from rabbits, use anti-rabbit secondary antibodies |
Inactive secondary antibody | Replace with a new batch of antibodies |
Inactive ABC reagents | Replace with a new batch of reagents |
Defective or incompatible enzyme/substrate system | Replace with a new batch of reagents |
Inadequate substrate incubation time | Increase the substrate incubation time |
Incorrect mounting medium | Choose a correct mounting medium |
Reagents applied in wrong order or steps omitted | Check notes or procedure used |
Sources | Solutions |
Inadequate washing of sections | Wash at least 3 times between steps |
Tissue contains endogenous enzyme such as peroxidase or alkaline phosphatase | Block endogenous enzyme activities using 3% hydrogen peroxide (block peroxidase) in methanol or levamisole solution (block AP) prior to incubation of primary antibodies |
Tissue contains endogenous biotin activity | Block endogenous biotin activity using the avidin/biotin blocking reagent prior to incubation of primary antibodies. |
Non-specific binding of primary antibodies to tissue or antibody concentration was too high | Non-specific binding may be reduced by using higher dilution of primary antibodies |
Non-specific binding of secondary antibodies to tissue | Treat tissue with normal serum from the same species as secondary antibodies |
Diffusion of tissue antigen due to inadequate fixation | Increase duration of postfixation |
Mouse antibodies used on mouse tissues | Treat tissue with MouseOnMouse blocking reagent prior to the primary antibody incubation |
Sections dried out | Avoid sections being dried out |