Can creatinine levels vary in healthy adults?

Question

Hello doctor,

This person is 43 years old and male. He takes weekly urine screen at the same time of each week. The screen measures creatinine in mg/dL and the previous creatinine results are as follows: 117, 221, 179, 88, 147, 235, 201, 173, 100, 92, 123 and 142. About a year ago, he had levels as low as 17 and 22. Are these normal range of numbers? If not, what might explain this person's wide range in creatinine? The tests are to monitor for alcohol use and I believe there is a possibility that this person is falsifying the tests. If you know any studies, then you could point me to that to have a look at creatinine variations in healthy adults that would be helpful. Thank you.

Answer 1

Hello,

Welcome to icliniq.com.

This is a quite interesting query.

Firstly, the thing you should know is that the creatinine is a byproduct of muscle metabolism which has no role to play in blood.

The amount of creatinine removal from urine depends both on the production from muscle as well as the ability of kidneys to remove it.

So, it will decrease if renal functions are compromised or the person is immobilized or inactive for long period (low production by muscle).

It will increase if there is excessive muscular activity or damage to muscle or in severe dehydration.

The normal range is very broad and varies in men and women. In men it is 16 to 24 mg/kg in 24 hour urine collection.

The values which you have mentioned of last week are acceptable, but a year back these are too low. Please check whether the reports are given in same units.

Many published studies have been shown a wide range of creatinine excretion in urine in normal males.