Patent ID: 7363168
Filing Date: 2008-04-22
Classification: C12Q,G01N

Abstract:
1. A method for determining an absolute or relative quantity of a target nucleic acid in a sample, which includes calculating a baseline for a plurality of sample wells in a sample block cycling through cycles of a PCR reaction, said method comprising: (a) detecting an actual optical signal in a well containing the sample during a PCR reaction; (b) plotting the intensity of said actual optical signal observed in said well as a function of cycle number for said well to obtain a first plot; (c) automatically determining from said first plot a starting cycle and an ending cycle for said well, wherein the ending cycle is a last cycle before the target nucleic acid becomes detectable during the PCR reaction and the starting cycle is a first cycle after initial variability of the amplification reaction subsides, the first cycle being before the ending cycle; (d) determining a best fit line to points between and including the starting and ending cycle; (e) performing steps (a)-(d) independently for each of said plurality of wells; (f) calculating said baseline independently for each of said wells using the respective best fit line; (g) generating a working curve independently for each of said wells by subtracting the respective baseline from the respective first plot; and (h) using the at least one working curve to detect a corresponding amplified target nucleic acid.