In my clinical experience when the GFR approaches zero the creatinine goes up between 1 and 2 mg/dL everyday.
However ai was working out a story problem for an acute renal failure and when I calculated how much the creatinine would rise it was 3.3 per day. Here is how I calculated this:
- Total body creatinine: 420 mg
- This assumes that creatinine is equally distributed through out total body water. So 42 liters (60% of 70kg) times 1 mg/dl times 10 dL per liter
- New creatinine: 1400 mg
- 20 mg of creatinine generation per kg body weight, 70 kg body weight
- New total total body creatinine 1820 mg
- add the first two figures
- New creatinine: 4.33 mg/dL
- Divide the total body creatinine (1820 mg) by total body water (420 dL):
Did I do my calculation wrong? The total body creatinine calculation of 420 mg seems awfully low, especially if muscles create 1400 mg of new creatinine everyday.
Picture by The Doctr