Method for quantification of an analyte

The present invention relates to the quantification of analytes which are present in low concentrations but can be amplified or replicated under suitable conditions. In particular, it relates to quantification of a specific polynucleotide sequence within a sample containing polynucleotides. Methods are provided for quantifying the concentration of a nucleic acid in a nucleic acid sample. The methods include contacting the nucleic acid sample with an amplifying agent, amplifying at least one predetermined locus of the nucleic acid by subjecting the sample to a number of amplification, generating an amplification curve or array, calculating the first, second or n th order derivative of the amplification curve or array, determining a maximum, minimum, or zero value of the derivative, and using the maximum, minimum, or zero value to calculate the initial concentration of the nucleic acid in the nucleic acid sample.