What defines the analytical specificity of an assay?

The analytical specificity of an assay is primarily defined by its ability to accurately distinguish the target analyte from other substances present in the sample. This characteristic is crucial because it determines how well the assay can identify the analyte of interest without interference from other substances, such as similar molecules or background noise from the sample matrix. High analytical specificity means that the assay will give a positive result only when the target analyte is present, thereby minimizing false positives and ensuring reliable results.

In contrast, the other choices pertain to aspects that influence assay performance but do not directly define analytical specificity. For instance, the range of detectable analytes refers to the assay's breadth in terms of the different substances it can measure, which is related to its sensitivity and calibration but not its specificity. The time required for analysis, while important for practical applications, does not impact how well the assay differentiates the target analyte. Similarly, the complexity of sample preparation can affect the overall workflow and reliability of results but does not inherently define how specific the assay is in identifying the target analyte.