Sensitivity is a statistical term used to describe the ability of an assay to separate the blank from the specific analyte. Since there are a variety of methods used for determining sensitivity, the method must be known when comparing sensitivity between assays.
ISO11843-Part 4 describes one method for the determination of the Capability of Detection (CoD) and reflects the minimum level that is clearly distinguishable from Calibrator 0.
Capability of Detection should be seen as a method of validation, rather than the lowest concentration that can be measured.
Lower Limit of Quantification (LLOQ) is defined according to the FDA draft guideline as the lowest concentration of an analyte in a sample that can be determined with acceptable precision and accuracy,. The acceptance criteria are ≤ 25% for total variation and 100±25% for accuracy.