Roche Molecular Systems, Inc.

Roche Diagnostics Gmbh

F. Hoffmann-la Roche Ag

Martin Titz

Ronald T Kurnik

Systems and methods for processing PCR curves, and for identifying the presence of a parabolic-shaped PCR curve. Use of a piecewise linear approximation of a PCR curve enables a more realistic elbow value to be determined in the case of parabolic shaped PCR curves.

Determination of elbow values for PCR for parabolic shaped curves

Systems and methods for determining a transition value in a sigmoid or growth curve, such as the end of the baseline region or the elbow value or Ct value of a PCR amplification curve. Numerical determinations of the second derivatives and curvature values of a PCR data set are made. A Gaussian Mixture Model (GMM) function with parameters determined using a Levenberg-Marquardt (LM), or other, regression process is used to find an approximation to the second derivative values and to the curvature values, where the maximum values of the numerically determined second derivative values and/or curvature values are used as initial conditions for parameters of the GMM function. The determined parameters provide fractional Ct values. The Ct value(s) are then returned and may be displayed or otherwise used for further processing.

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Rotkreuz, Switzerland

Martin Titz