Tumor Biomarker In-Solution Quantification, Standard Production, and Multiplex Detection

Figure 1

Minimum detectable concentration versus actual point of detection. The minimum detectable concentration (MDC) is the earliest detection point for a biomarker that exceeds its normal level of expression. As biomarkers are secreted by both healthy and tumor cells, the average biomarker level can be above the assay’s detection limit before tumor initiation. Therefore, a cutoff value is required to differentiate between tumor-bearing and unaffected or benign conditions in serum assays. As tumor size increases, biomarker expression increases (blue circles). Although a biomarker is detected at or below the cutoff value, samples are not considered diseased until they exceed this cutoff value (the actual point of detection).