Limit of detection versus lower limit of quantification.
This chart demonstrates the difference between the limit of detection (LOD) and the lower limit of quantification (LLOQ). The LOD is defined as the lowest concentration at which 95% of the positive samples are detected, whereas the LLOQ is the lowest concentration that falls within the linear range of a standard curve. LOD depends upon the precision of the assay, and requires at least 40 replicates for determination of a positive sample. For the Microbial DNA qPCR Assays, LLOQ is sufficient to determine assay sensitivity.