Patent ID: 8145435

Claim:
A system for analyzing a polynucleotide-containing sample by time-dependent monitoring of an in vitro nucleic acid amplification reaction, said system comprising: an apparatus comprising a temperature-controlled incubator and a fluorescence monitoring device, said apparatus generating a data set comprising values proportional to the amount of analyte amplicon present in the in vitro nucleic acid amplification reaction as a function of time, said data set defining a growth curve; a processing device that analyzes the data set defining the growth curve, said processing device comprising software instructions to perform a vector analysis of at least a portion of said growth curve to identify a time-dependent feature indicating a transition from the baseline phase into the growth phase of said growth curve, said vector analysis comprising the steps of, (a) establishing a plurality of pairs of first and second vectors at different points on a time dimension of the growth curve, wherein each vector of a single pair of vectors among said plurality has the same origin, and wherein the head of the first vector and the head of the second vector of said single pair of vectors among said plurality are each positioned at different points on the growth curve, (b) calculating for each pair of vectors the value of an angle therebetween, thereby resulting in a plurality of calculated angles, with each point on the time dimension of the growth curve being associated with a different one of said plurality of calculated angles, (c) comparing the plurality of calculated angles with each other to identify a characteristic angle, and (d) identifying said time-dependent feature of said growth curve as the point on the time dimension of the growth curve that is associated with the characteristic angle, said characteristic angle being either the maximum angle among the plurality of calculated angles or the minimum angle among the plurality of calculated angles; and an output device in communication with the processing device.