1. Analytical sensitivity (detection limit)

1. The lowest analyte concentration detected is the analytical sensitivity or limit of detection of the detection system. This concentration limit is especially important for drug testing in court, and it is critical to hope that the test will know whether there is any drug in the sample. In addition, tumor markers and many specific proteins should have a minimum detectable concentration or a certain amount; such as: prostate-specific protein (PSA), which is important information for monitoring recurrence after patient treatment; Minimum requirements for meaningful amounts of specific proteins to be specified. The negative or positive nucleic acid test report also requires an explanation of how much virus the smallest copy of nucleic acid that can be detected is equivalent to. Therefore, determining the lower reportable limit of a detection system is an important analytical performance.

2. Currently, the terminology for detection limit is confusing. Manufacturers use various terms such as: sensitivity, analytical sensitivity, minimum detection limit, functional sensitivity, limit of detection, limit of quantitation, etc. . As yet there is no standard definition, so it is necessary to understand what each word actually means and the experimental way in which it is determined, how the data is processed, how an estimate is made from the data, and whether the estimate is useful for the medical application of the test. The analytical sensitivity described below is divided into the lower detection limit with qualitative meaning, and the biological detection limit and functional sensitivity with quantitative meaning.