On the interpretation of affirmative follow-up tests in immunoassays: what must not be done?

The integrity of analyses and their limitations fall firmly within the laboratory domain. The shortcomings of analyses performed by immunoassays are well recognized. When a result is unexpected or in doubt, the laboratory may perform additional tests to substantiate the integrity of that analysis, such as repeat analysis by an alternative method, serial dilutions, or antibody blocking regents. Though commendable practice, these extra tests could in some cases lead to a false sense of assurance, misleading clinicians and wasting resources. I would like to highlight the use and misuse of these tests.