Effects of Blood Mark Screening Reagents on the Process of Nucleic Acid Extraction and Amplification for Personal Identification

Biological evidence collected at crime scenes plays a crucial role in confirming the identities of individuals. Blood, particularly is a commonly encountered bodily fluid at such scenes, and fluids containing blood, such as saliva, semen, vaginal fluid, and urine, are excellent tools for personal identification. The accurate identification and collection of blood is essential for reconstructing crime scenes and subsequently identifying suspects. Blood is commonly found at crime scenes distributed across various surfaces and objects, serving as important evidence. The analysis of bloodstains provides valuable information about the events that occurred during a crime, and bloodstain analysis is a vital tool for reconstructing events at a crime scene. Initially, the presence of blood is confirmed based on factors such as time, conditions, and environment. Invisible bloodstains are identified by visually inspecting suspicious areas, followed by performing serological preliminary and confirmatory tests to determine the presence of blood. Notably, luminol and KM reagents are commonly used reagents at crime scenes. In cases where bloodstain analysis indicates a positive result, personal identification is conducted using nucleic acid (DNA) alongside confirmatory tests. Experimental results show that the luminol reagent exhibits higher sensitivity than the KM reagent. During DNA amplification, it is observed that factors such as time, conditions, and environment influence DNA amplification more than reagents. Furthermore, the STR marker D1S80 showed a more significant reduction compared to the TH01 marker. This experiment holds potential applicability in various crime scenes, offering foundational data regarding results based on sample types, temperature, environment, and time.