I have been on Apixiban for six months and went to the Nurse this morning for a blood test to see how my kidneys and liver were coping. I happened to say to the Nurse the last time they couldn't test it as my blood had coagulated in the tube, she went on to say it looked thick this morning!! She also asked did I ask to go on Apixiban as they could not test if it was working or not, I didn't ask to go on it the Cardiologist put me on it after Riveroxaban not agreeing with me. My question is how do I know it is working especially as she said it looked thick, have I cause to worry? I didn't ask her as she didn't even know how to spell it I had to tell her.