Im really confused about my dads D-dimer levels after his COVID recovery. His first test showed 1800, but we didnt find out until five days later. He wasnt showing any clotting symptoms, so we checked with a doctor who recommended blood thinners. We decided to get another test done at a more reliable lab two days later and it came back at 160. He had been taking dabigatran 150 BD during those two days. We re-tested after 15 days, and the D-dimer was 180. Im trying to figure out if the blood thinner could have caused such a big drop from 1800 to 160, or if its safe to just disregard the first test as incorrect and stop the meds. Could you help me understand whats going on?

Physician opinion is advised to the patient.