TST or MD?

Good afternoon!  I have a quick question and it was suggested that I contact you for the answer.  Question is: If a student has 2 possible attendance codings, which one would I use?  The student in question currently has a TST for testing, but then he was taken out early so he would have an LFU (unexcused), and he came back with a Doctor's note, which is an MD. Do I use the MD or keep the TST?  Just didn't know how important it is to keep the TST testing code.  Let me know when you get a chance.  Thank you!