Patent ID: 8239137

Claim:
A method for determining the presence of a nucleic acid in a sample, comprising: providing a reaction mixture suspected of containing a nucleic acid, wherein said reaction mixture is in a form suitable for eliciting a detectable signal from said suspected nucleic acid, detecting said signals from said reaction mixture in known intervals, transforming said signals into measurement data, and creating from said measurement data a growth curve through a mathematical algorithm, wherein said mathematical algorithm comprises a mathematical growth curve model formula f ⁡ ( x ) = p 1 · ( 1 + p 2 · x ) + p 3 [ 1 + exp ⁢ { - p 4 · ( x - p 5 ) } ] · [ 1 + exp ⁢ { - p 6 · ( x - p 7 ) } ] or its mathematic equivalents, wherein x is a measure of the time or sequence of the measurements, p 1 is the intercept of the growth curve for the start of the reaction, p 2 is the relative drift of the base line, p 3 is the distance between the base line and the saturation line, p 4 is the slope at the inflection point of a first multiplicative sigmoid function representing exponential growth, p 5 is the inflection point of a first multiplicative sigmoid function, p 6 is the slope at the inflection point of a second multiplicative sigmoid function representing saturation growth, and p 7 is the inflection point of a second multiplicative sigmoid function, wherein optimal values of the parameters are determined by a non-linear aggression fitting algorithm to said measurement data, determining from said growth curve whether said nucleic acid is present or absent in said reaction mixture.