The original CODIS database based on 13 core STR loci has been overwhelmingly successful for matching suspects with evidence. In order to increase the power of discrimination, reduce the possibility of adventitious matches, and expand global data sharing, the CODIS Core Loci Working Group determined the expansion of the CODIS core loci to 20 STR plus three additional "highly recommended" loci (SE33, DY391, Amelogenin) Hares, 2015Hares, , 2012. The QIAGEN Investigator 24plex QS and Investigator 24plex GO! Kits are 6-dye multiplex assays that contain all markers of the expanded 23 CODIS core loci along with a unique internal performance control that is co-amplified with the STR markers. The "Quality Sensor" generates additional information for quality control and performance checks. Investigator 24plex QS is designed for purified DNA from casework and reference samples, whereas 24plex GO! is dedicated to direct amplification of reference samples, like blood or buccal cells on FTA or swabs.A developmental validation study was performed on both assays. Here, we report the results of this study which followed the recommendations of the European Network of Forensic Science Institutes (ENFSI) [3] and the Revised Validation Guidelines of the Scientific Working Group on DNA Analysis Methods (SWGDAM) [4]. Data included are for PCR-based procedures e.g. reaction conditions, effects of PCR annealing temperature variations, amplification cycles or cyclers, sensitivity (also in the context of the Quality Sensor), performance with simulated inhibition, stability and efficiency, precision, reproducibility, mixture study, concordance, stutter, species specificity, and case-type samples. The validation results demonstrate that the Investigator 24plex QS and Investigator 24plex GO! Kits are robust and reliable identification assays as required for forensic DNA typing in forensic casework analysis and databasing.

We developed and validated the Investigator Argus X-12 QS Kit, which allows co-amplification of 12 Xchromosomal markers arranged in 4 linkage groups. The updated kit uses the Fast Reaction Mix 2.0 that allows short PCR cycling protocols and provides high inhibitor tolerance. The autosomal marker D21S11 was added to enable alignment of the Investigator Argus X-12 QS Kit profile with a profile from any other autosomal STR kit from the expanded CODIS or ESS markers, and to minimize the risk of sample mix-ups. A Quality Sensor (QS) was introduced as an internal control to monitor PCR performance. SNP primers were added to overcome allele drop out due to known mutations in primer binding sites. Furthermore, more alleles were added to the allelic ladder. 2015 Elsevier Ireland Ltd. All rights reserved.

Novel STR Multiplex PCR assays addressing the European STR standard set (ESS) of loci as well as the new expanded CODIS core loci set have been developed. The Investigator 24plex QS and 24plex GO! Kits cover the expanded CODIS set and are designed for the amplification of purified DNA from casework and reference samples, or direct amplification of common database samples, respectively. The Investigator ESSplex SE QS Kit covers the ESS loci and SE33. All three kits have an internal performance control, the quality sensor (QS), included as component of the corresponding primer mixes. QS allows the user to monitor the performance of the PCR and to distinguish between inhibited and degraded samples. 2015 Elsevier Ireland Ltd. All rights reserved.