Question

Explain using examples, ‘how’ and ‘why’ you would collect Sensitivity and Specificity data when performing a Validation Study on a new DNA STR Profiling Kit.

Answer 1

STR DNA/PCR kits are used in molecular biology for the purpose of forensics, human identity and paternity testing.STR means short tandem repeats.

Validation of any new kits are very important as they form a part of forensic quality assurance system since they assure precision, reproducibility, sensitivity and linearity. Always while validation testing is conducted, the samples taken are known evidence samples.

• Sensitivity is defined as the ability of a system to yield correct and reproducible results.
• Specificity is the ability of the test to detect the STR at set threshold levels.

Both sensitivity and specificity data determine how accurately the test kit performs such that when new samples are tested, the test is reliable.

Placing positive and negative controls, establishing threshold levels, threshold temperatures and speed in the test equipment are some of the measures to determine the accuracy of the test kit for new samples.

Many set standard guidelines by organizations including European DNA profiling group, European network of forensic science institutes and the Federal Bureau of Investigation's DNA advisory board help in the development of quality assurance measures especially in DNA testing quality infrastructure methodologies.