((18.1 mg /2) * 125 ml/min) / 0.00177mg/ml = ?

Perhaps some detail would be better.

I am trying to calculate the renal clearance of a drug in volume/unit time. The values I am given at the start are in per hour, however GFR is within mL/minute. This means a bit of changing calculations around in order to complete the calculation. A few times I messed around, I would get different answers e.g. 639, 564, 639,124.

I can't quite remember how I did it to get the value of 564 though. Therefore, I am thinking that one of the two must be right, 639.124 or 639,124.

Clearance value should come out as volume/unit time (usually as mL per minute but can also be per hour. In this case, mL does not become squared.

WaveForm Oct 23, 2016

edited by
Guest
Oct 23, 2016

edited by Guest Oct 23, 2016

edited by Guest Oct 23, 2016

edited by Guest Oct 23, 2016

edited by Guest Oct 23, 2016

#12**+5 **

AGAIN: if 18.1 is mg/ml or mg/liter (changed to mg/ml) your units will be correct ! Are you SURE 18.1 is mg/hour ??????

ElectricPavlov Oct 23, 2016

#1**+5 **

Are you sure you entered this question correctly? The answer will be in the units of ml^2/min

ElectricPavlov Oct 23, 2016

#4**+5 **

SWX: Because of the dimensions given in the question

It has:

(mg x ml/min ) / (mg/ml) = (mg ml)/min x ml/mg = (ml ml)/min = ml^2/min

ElectricPavlov Oct 23, 2016

#5

#6**+5 **

Hang in there...it gets easier with practice and time.......You can do it !

ElectricPavlov
Oct 23, 2016

#8**+5 **

Give me the original question and units, and I am sure we can get this staightened out ! your equation has incorrect units.

ElectricPavlov Oct 23, 2016

#9**+5 **

IF it is 18.1 mg/ml instead of 18.1 mg/2 your answer will come out in units of ml/min

ElectricPavlov Oct 23, 2016

#10**0 **

It is 18.1mg because that is the amount for 2 hours. I divide it by 2, to get it for 1 hour. The answer to that is 9.05

I would do replies, but I have no idea how to do that on this site.

WaveForm Oct 23, 2016

#11**+5 **

OK so it is 9.05 mg/HOUR THAT equals .150833 mg/min

Use THAT to match your units

BUT you still are missing something in the units....sorry......give me the original question please!

ElectricPavlov
Oct 23, 2016

#12**+5 **

Best Answer

AGAIN: if 18.1 is mg/ml or mg/liter (changed to mg/ml) your units will be correct ! Are you SURE 18.1 is mg/hour ??????

ElectricPavlov Oct 23, 2016

#13**0 **

Thanks for your help, it made me realise where I was messing up. After some changing around of the equation, it made more sense to me.

Basically, I had to change it to ( (18.1 mg/hour^-1) /2 ) / 0.00177 mg/ml = This will get me the answer per hour (5112 ml/hour) as both of the mg get cancelled out in the equation.

Then I have to do (5112 ml/hour) / 60 = to get my answer in minutes.

Obviously would be easier to convert 9.05 to mg/minutes but then I would not be able to keep track of the 18.1 and 9.05 mg amounts.

Thanks for your help nonetheless. It really brought clarity to me and helped me figure out where I was going wrong. (i.e. My answer was to be compared to 125ml/min, not have that number in the equation).

WaveForm
Oct 24, 2016