59yearold

I went in for normal blood work. I was told a number was high for kidney function. I'm not sure if it is creatinine. I think that might be the bun ratio. They said that 17 is normal and mine was a little high at 20. A month later I went in for a recheck and it is now 30. I have been taking enalapril (vasotec) for 20 years. He says this can raise the level (I think creatinine). He has taken me off of my blood pressure medicine for two weeks and then will have another blood test. Everything else in all by blood work is perfect. I am 65 and wonder if age increases the levels. But, it was strange how it was 20 and then 30. Please help me to understand all this. I am very nervous. I've read too much on the internet and now am worried.