Only the lab that runs the tests. They would have to go along with the lie, because it would have to be confirmed by their report. Some might think this unlikely or even impossible, but it's been done before. Remember a few years ago when the FBI crime lab was shown to have lied about lab results in dozens of cases, including high-profile cases?
So I think your point is very well taken.
How were the lies about lab results in those FBI cases you referred to proven/shown? By the lab reports themselves? Just curious.