Patent ID: 7668660

Claim:
A method of providing information on the likelihood of a result arising due to contamination in a method of analysis: the method of analysis including a threshold which determines the analysis protocol to be applied to the analysis of DNA in a test sample; the method of providing information including: in respect of one or more negative controls, obtaining information on whether or not DNA is suggested as present in the one or more negative controls; determining the probability of DNA being suggested as present in the one or more negative controls, the determination being based on the number of the one or more negative controls which suggest DNA is present compared with the total number of the one or more negative controls considered; the probability of DNA being suggested as present in the one or more negative controls being equated to the probability of the test sample being contaminated; the method of providing information further including: in respect of one or more DNA samples, obtaining information on whether or not DNA is suggested as present in the one or more DNA samples; obtaining information about the quantity of DNA in the one or more DNA samples; in respect of one or more second negative controls, which may be the same or different to the one or more negative controls, obtaining information on whether or not DNA is suggested as present in the one or more second negative controls; obtaining information about the quantity of DNA in the one or more second negative controls; simulating one or more mixtures, the mixtures each being formed from a pairing of a second negative control and a DNA sample taken from amongst the one or more second negative controls and the one or more DNA samples; establishing the proportion of mixtures for one or both of the following types of simulated mixture: DNA suggested as present from second negative control only; DNA suggested as present from both DNA sample and second negative control; determining a likelihood ratio in respect of a result arising which exceeds or which matches or exceeds the threshold in the method of analysis for one or both of the types of simulated mixture.