I have a cortisol level of 3.1 and 3 test of my gfr 56 each time what does that mean thank you?

Your statement is not clear enough. If the cortisol level was measured in the morning and for 3 times (?) it was 3.1, you may have hypoadrenal insufficiency but further test needs to be done to confirm this condition. GFR less than 60 cc/min for 3 times indicates you have mild chronic kidney disease, stage 3A. I wonder cortisol was measured because you have low sodium (Na) or high potassium (K).

Do you mean blood or saliva or urine cortisol. Time of day? Saliva is best. eGFR means your kidney function may not be normal using this measurement. Discuss with someone who knows you. As in Dr. who ordered the tests.