Can a person dilute blood by drinking too much water to actually make their kidney function appear better than it actually is?any more accurate tests

Kidney function test: Can person dilute blood by drinking 2 much water 2 make their kidney function appear better than it actually is?any more accurate tests. ANS: Yes test is serum creatinine 2 estimate eGFR. Depends on how concentrated/dilute ur blood is .Creatinine tends 2 b lower b4 u get out of bed as water moves to blood & higher when u stand water pools in legs. 24 hr Creat clearance test is the gold standard