Needle stick injury, patient serology tests screen for blood-borne infections such as HIV, hepatitis B, and hepatitis C, and assess aspartate aminotransferase/alanine aminotransferase (AST/ALT) and alkaline phosphatase levels. These tests detect antibodies or antigens, indicating potential pathogen exposure. Timely testing and post-exposure prophylaxis are crucial to minimizing infection risk after such incidents.