Table 3.

Properties of interfering substances.

□ Unique to an individual □ Interfering antibody concentration can change over time within the same individual □ Low affinity polyspecific antibodies can be present in high concentrations or high affinity in low concentrations □ Can produce falsely high (false-positive) or falsely low (false-negative) results □ May interfere within one or more manufacturers' immunoassay systems but not necessarily in all assays □ May interfere in a number of immunoassays for different analytes □ The inclusion of one or more interference blocking agents in manufacturers' immunoassay reagents may be insufficient to overcome the interference