The confocal microscopic optics utilized in Single Molecule Counting technology rotate and scan through the bottom of a detection vessel. The intensity of fluorescence encountered in the interrogation space (orange dot) is captured as a function of time. The measured fluorescence is sequestered in 100 micro second time bins as shown below.
A threshold of signal intensity (dotted line) is applied across all time bins and only bins with fluorescence above the threshold are counted as detected digital events. Each of these counted digital events represents a single fluorescently-labeled molecule. The sum of digital events is equivalent to the concentration of analyte in the original biological sample. The Single Molecule Counting technology provides a reading range of more than 6 logs.