I am not a doctor, but I know that markers in blood can be all kinds of things, and they definitely don't have to mean that anything serious is wrong.
I get regular blood tests for my thyroid condition and PA, and as often as not they pick up on something being low or high. It's a nuisance, as I then have to go back to get another blood test, but they come back with the markers back to normal. It can be as simple as drinking (or not drinking) coffee on the day of the test, or as mentioned above having an infection somewhere.
I know it's easier said than done, but try not to worry. A cough can be a symptom of lots of things too. Let us know how you get on, but in the meantime, find a comedy or something to watch on TV and try not to dwell on the tests. 