@collegeprof A couple of years ago, I had a "split kidney function" test, that included a complicated examination and dye injection. It all had to be cleared by my nephrologist and oncologist beforehand. Measuring to see how each kidney was functioning, it revealed both were about the same. And due to my current brain fog, I cannot recall the reason for the test...

I have only had the creatinine eGFR testing done. But anything that will give us consistent and accurate results is tops in my book! We as patients should remember our hydration, diets, activity level, and even where the labs tests are run, in watching the trends for our kidney function.
Ginger