What is the definition or description of: seronegative?

See below: Having or being a negative serum reaction especially in a test for the presence of an antibody.

Negative blood test: I'll use HIV infection as an example. When someone is exposed to HIV and develops an infection, it takes time to detect that on a blood test. The typical antibody screening test will be positive within about a month of contracting hiv. The process of going from a negative test to a positive is called seroconversion. Sero refers to blood. You start seronegative, then become seropositive.