Went to ER with swollen calf, that also had rash. They did blood test and the results indicated that my eGFR was approx. 75. Determining that I had an infection in my leg, the ER folks prescribed two types of antibiotics for 7 days. I did a follow up with my primary physician 9 days after the ER visit, who had me take a blood test, and that yielded a result of eGFR of 55. ( What has me concerned as well, is with the ER's blood test, my Red Blood Count = 4.12, Hemoglobin = 12.1, Hematocrit = 38.7% and Red Cell Distribution Width was 48.8 %. ) I also have anxiety issues and this isn't helping. Seems odd that the eGFR would drop so fast. Is it possible for the numbers to change so rapidly?