I had covid a month ago with mild inflammation in both lungs. took dexamethasone. i did a lab today for co2 blood test and mine was 21. i didnt eat much and ate hours before the test. the standard range says 22-29 is this dangerous? is it related?

Probably of no significance at all. There are many reasons for a slightly low CO2, but if you are feeling well and healthy it is not likely to be important. The best way to interpret labs is to see them as clues, part of a bigger puzzle where how you feel is the most important piece. Minor variations in lab values are rarely important, but should always be looked at in the bigger picture.

If you are experiencing symptoms, you may have long COVID-19. A virtual consult with HT is available to review the full set of lab results and history. Breathing problems may be prolonged and if this is ongoing, a chest image and pulmonary function test may be indicated. Have a Flu vaccination, COVID-19 vaccination as indicated.