Creatinine Clearance Formula (crockoft gault)

I have another conundrum and was looking for help.

I have to calculate Creatinine clearance in an excel spreadsheet. It is a weight based formula where
CrCl=((140-age)*Weight/(72*Creatinine))*0.85 if female.

I have this equation already made
=IF(Q4="0",((140-P4)*U4*0.85/(72*AA4)),((140-P4)*U4/(72*AA4)))

My problem is that the weight you use fluctuates depending on how overweight the patient is. If their actual weight (cell T4) is less than their ideal weight (U4){ie T4/U4<1} then you use actual weight, if they are obese (defined as T4/U4=>1.3) then you use adjusted Body weight(which I have already calculated in V4). If they are between these two ranges (1<x<1.3), you use ideal body weight (U4).

I know this is complicated, but I can't find a way to build an IF function into the above equation that I already put together to account for using these different weights. Anyone have any pointers?

Attached the spreadsheet incase it helps someone understand my question better.

Thank you
Andrew

OK, I see now. I have a lot to learn. It does make sense now that I see it though. I didn't know you could use another IF for the false value of the first IF command. Thank you

Hi! I am using this formula for an excell sheet I am making however I am not getting the correct answer, the numbers are coming up to be way too high and im not sure what I am doing wrong, If anyone knows how to help I would greatly appreciate it