I also have only one kidney... i just looked it up.. here is what it said. what is your creatinine level?
Serum Creatinine: Creatinine is a waste product in your blood that comes from muscle activity. It is normally removed from your blood by your kidneys, but when kidney function slows down, the creatinine level rises. Your doctor should use the results of your serum creatinine test to calculate your GFR.
Your GFR tells how much kidney function you have. It may be estimated from your blood level of creatinine. If your GFR falls below 30 you will need to see a kidney disease specialist (called a nephrologist), Your kidney doctor will speak to you about treatments for kidney failure like dialysis or kidney transplant. A GFR below 15 indicates that you need to start one of these treatments.
At increased risk Risk factors for kidney disease (e.g., diabetes, high blood pressure, family history, older age, ethnic group) More than 90
1 Kidney damage (protein in the urine) and normal GFR More than 90
2 Kidney damage and mild decrease in GFR 60 to 89
3 Moderate decrease in GFR 30 to 59
4 Severe decrease in GFR 15 to 29
5 Kidney failure (dialysis or kidney transplant needed) Less than 15
i would have it checked again in a few days, sometimes your levels go up an down, depending on your salt intake i think. or maybe what you ate.