In the UK, it is STANDARD practice in all laboratories that I know to use either the phrase "No Antibodies Detected", or, more frequently, "No Atypical Antibodies Detected", as the latter also includes such things as the iso-antibodies of the ABO and H Blood Group Systems. Indeed, some go further still and use "No Atypical Allo-antibodies Detected", as this covers such findings as an auto-anti-H, auto-anti-I and auto-HI, as well as the ABO and H iso-antibodies.
These phrases do not mean that there are no atypical allo-antibodies detected. It would be an incredibly rare set of screening cells and antibody identification panel cells that would both express, for example, the HJK antigen, or any other genuine low prevalence antigen.
In some cases, where an atypical allo-antibody IS detected, but it is known to be clinically-insignificant (such as anti-Kna), we may use the phrase "No Clinically-Significant Atypical Allo-antibodies were Detected" (or words to that effect).
One thing is for certain, and that is that a UK Reference Laboratory (and most hospital laboratories) worth their salt would report out as "Negative", or "No Antibodies", although, even using the phrases I've quoted above, occasionally the phrase, "All Clinically-significant Allo-antibodies have been Ruled Out using etc.", or words to that effect.
MIND YOU - you have to remember that I am RENOWNED for being a pedant - but I learned it from a few good sources; Peter Issitt, Carolyn Giles and Joyce Poole (to name but three).