DNA Specimen Collection
Performing DNA or deoxyribonucleic acid at the laboratory, initial testing is often conducted at the crime scene to determine the type of biological material in question. Screening/Testing for the presence of biological materials may also be conducted in the laboratory to determine if a specific biological fluid may be present. Most biological screening tests are presumptive in nature and do not specifically identify a bodily fluid, such as blood, urine , saliva.
Physical samples of evidence like hair, fingernail, bone , teeth , feces , cells and tissue can also be screened for dna.