Why does NSAC don't require blood to be drawn for prizefights?

Is there any reason why the NSAC do not require any blood drawn as part of their testing or do they require this at least once? I'm curious. Do they think that the fighter's health and probably safety might be jeopardized with this kind of testing and might lead to the cancellation of a fight revolving around money? Like if the syringe used accidentally hit some nerves or a possibility of developing an infection from the incision point. Is blood testing really quite irrelevant compared to urine testing. I want to hear what Keith Kaizer has to say about integration of Olympic type testings being integrated in a prizefight. I'm pretty sure there are reasons why they have the kind of testing they have now.