How would I obtain a glucose test taken by EMS?

Since the legal topic area is indicated above as "DUI" I am assuming based upon your question  that you have been charged with DUI, that a blood test was taken and you want the results of the blood test. That information is within the control of the police/DA. Each county is different in how they handle providing the results of blood tests to defendants. As a general rule my experience has been that if your case is still in General Sessions Court and they intend to use the results of the blood test at the preliminary hearing to get your case bound over to the grand jury, then they wiii   provide the results in General Sessions Court. If you plead guilty in General Sessions Court or waived the preliminary hearing and it was bound over to the grand jury without a preliminary hearing, then the lawyer is correct that you will not see the results of the blood test until the discovery process in criminal circuit court.