What type of sample was used to test workers at GATTACA for a match with crime scene evidence?

In the context of GATTACA, which is a film that explores themes of genetic engineering and DNA profiling, the method employed to test workers for a match with crime scene evidence prominently involves the use of blood. Specifically, DNA from blood samples is a highly effective means of identification, as it contains a complete genetic blueprint that is unique to each individual, allowing for precise matching with evidence found at crime scenes.

Blood samples provide high-quality DNA, which is crucial for forensic analysis because they can supply a significant amount of genetic information without the degradation often seen in other biological materials over time. While saliva, hair, and skin cells can also be used for forensic purposes, they are generally considered less reliable than blood in terms of the quantity and quality of DNA that can be extracted for matching purposes. Therefore, the emphasis on blood samples in GATTACA aligns with the practices used in real-world forensic science.