[Comparison of the Forensic Testing Performance of Six STR Kits]

Area of Science:

• Forensic science
• Molecular biology
• Genetics

Background:

• Short tandem repeat (STR) genotyping is crucial for forensic DNA analysis.
• Evaluating the performance of commercially available STR kits is essential for optimizing forensic testing protocols.

Purpose of the Study:

• To compare the technical performance indicators of six commonly used STR kits.
• To assess the capabilities of these STR kits in forensic testing applications.

Main Methods:

• Analyzed STR genotyping results of forensic DNA standard sample 9948 using six different STR kits.
• Evaluated detection sensitivity, allelic drop-out/in, allele peak height, and heterozygote balance.
• Assessed tolerance to PCR inhibitors including humic acid, heme, indigo, calcium ions, and EDTA.

Main Results:

• Identifiler™ Plus, AGCU EX28CS, and VersaPlex™ 27PY had a detection sensitivity of 100 pg, while FastDirect™ 25A, NHID® 25A, and Verifiler™ Plus reached 50 pg.
• NHID® 25A demonstrated superior tolerance to humic acid, heme, and calcium ions. VersaPlex™ 27PY excelled with indigo, and FastDirect™ 25A with EDTA.
• Most kits showed comparable or better inhibitor tolerance than Identifiler™ Plus, with variations in specific inhibitor resistance.

Conclusions:

• Newer STR kits (AGCU EX28CS, FastDirect™ 25A, NHID® 25A, VersaPlex™ 27PY, Verifiler™ Plus) demonstrate no overall disadvantage compared to Identifiler™ Plus.
• These kits exhibit comparable or superior performance in detection sensitivity, allelic drop-out/in, allele peak height, heterozygote balance, and inhibitor resistance.