How is measured creatinine clearance calculated?
Creatinine clearance is calculated using timed urine collection. The time is often 24 hours but can be as short as 4 or 6 hours. The clearance formula and an example is as follows.
where A is the generic clearance formula. B substitutes some typical values. C. Shows that the units all cancel out except mL/min.
Note: to convert the 24-hour measurement to the conventional units of mL/min, one needs to convert 24 hours to minutes, by dividing by the number of minutes in a day, 1440. All the units cancel each other out except mL/min.