Internal Validation of the Investigator Argus X-12 QS Amplification System for Reduced Volume to Improve Cost Effectiveness in Forensic DNA Analysis

The Investigator Argus X-12 QS Kit is specifically designed for the rapid and reliable generation of DNA profiles from various sample types and particularly useful for kinship confirmation, paternity testing and analysis of mixed samples involving multiple individuals in forensic investigations. The kit enables the co-amplification of 12 X-chromosomal markers, delivering reliable and informative genetic data for complex forensic investigations. The Investigator Argus X-12 QS Kit was previously validated in the DNA laboratory of the Government Analyst’s Department, following the manufacturer's guidelines for full-volume (25 µl) reactions, establishing a working range of 0.5 ng and 0.75 ng. To minimize annual chemical costs, an internal validation was conducted using a reduced reaction volume of 15 µl. This validation assessed the system's sensitivity, repeatability, reproducibility, mixture interpretation, and contamination study by amplifying a female and male DNA samples from a case study and the control DNA 9947A of the Investigator® Argus X-12 QS PCR Kit. Sensitivity studies revealed that the optimal DNA input range for achieving a complete profile was between 0.5 ng and 0.75 ng, which aligns with the manufacturer's recommended minimum DNA template input of 0.5 ng. The system's repeatability and reproducibility were confirmed through consistent results observed across repeated studies. In mixture analysis, 1:1 ratio of male: female samples successfully detected all alleles contributed by both individuals. However, when the ratio increased to 1:3, allele dropout was observed. The internal validation of the Argus X-12 QS Amplification System with a reduced reaction volume of 15 µl provides a cost-effective solution while maintaining its high effectiveness in forensic DNA analysis, offering enhanced capabilities for handling complex casework.