Positive and negative controls are essential for all forensic data analyses. GeneMarkerHID software has capability for the analyst to specify positive control samples to automatically detect any problems with the allele calls of the positive control(s). Each analysis template can accommodate two different positive control genotypes. This provides automatic concordance check for both DNA extraction and PCR amplification positive controls. Typically, these are different genotypes as the extraction control DNA source may vary from laboratory to laboratory and the PCR amplification positive control is typically supplied with the PCR kit. Negative or reagent blank controls are evaluated and flagged if any peaks are detected, with the exception of negative controls in chemistries with two quality sensors, such as the QIAGEN Investigator® chemistry. Figures 1 and 2 provide examples of the control concordance summary bar and flags that indicate non-concordance.
Figure 1: The above screenshot shows positive control concordance. The information is listed in the Summary Bar at the bottom of the analysis screen.
Figure 2: The figure above indicates a problem in the positive control for this run. The Summary Bar lists PC error 1/1 and the electropherogram has red vertical bars at the bins of the expected peaks for the selected positive control. If any detectable peaks occur in the negative control the peaks will be flagged and the Summary Bar will indicate NC error.