Which substances are commonly reported to interfere with laboratory assays and should be documented?

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Substances that can alter assay readings and must be documented include biotin, certain dyes, and NSAIDs. High-dose biotin can interfere with many immunoassays that use biotin-streptavidin components, producing misleading results regardless of the patient’s actual condition. Dyes can affect detection methods, especially in colorimetric or spectrophotometric assays, by changing absorbance or signaling in unintended ways. NSAIDs can alter results by affecting enzyme activity, binding interactions, or cross-reactivity in various tests, leading to inaccurate values.

Because of these potential interferences, it’s essential to document any use of biotin supplements, medications containing dyes, and NSAIDs (as well as other substances that might affect a specific test) so the laboratory can interpret results correctly. The other options don’t capture the range of common interferents: water and oxygen aren’t typically listed as standard assay interferents requiring documentation; limiting to vitamins omits biotin and NSAIDs; and the idea that all medications never interfere is not accurate.