Final answer:
In handling forensic specimens for a sexual assault case, the phlebotomist's primary concern is proper documentation and the chain of custody, along with maintaining specimen integrity and confidentiality, wearing PPE, and timely collection.
Step-by-step explanation:
The most important concept a phlebotomist must adhere to when handling forensic specimens, particularly for a sexual assault case, is proper documentation and chain of custody. This ensures that the evidence collected can be legally and scientifically used in court. Maintaining the integrity and confidentiality of the specimens is also critical, as is collecting specimens within a specified time frame and wearing personal protective equipment (PPE) to prevent contamination and ensure the safety of the phlebotomist.