Question: Hello, my question is how much creatinine varies in a healthy, adult male. This person is 43 years old, male and white. He takes weekly urine screens at the same time each week. The screens measure creatinine in mg/dL, and the creatinine results the last weeks have been as follows: 117, 221, 179, 88, 147, 235, 201, 173, 100, 92, 123, 142. In previous months, about a year ago, he had levels as low as 17 and 22. Are these normal ranges 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's a possibility that this person is falsifying the tests. If you know of any studies you could point me to that have looked at creatinine variations in healthy adults that would be helpful.

Thank you! Great reply! Let me give you some more background information.

I'm not as concerned with his kidney functions as I am to whether he is trying to cheat his alcohol tests. The tests he takes are EtG/EtS tests that are supposed to measure alcohol use back for approximately 80 hours. The tests contain the creatinine marker to measure specimen validity.

Immediately after he began testing, creatinine levels were a roller coaster, a 20 one week, 150 the next, back to a 30 the next week. This pattern continued for about two years. Then about 6 months ago his creatinines leveled out at: 117, 221, 179, 88, 147, 235, 201, 173, 100, 92, 123, 142 each week, respectively. So I'm trying to figure out if he was cheating before, if he's stopped now, or if he's still cheating, or what else might be going on. Are ranges of 88-235 a normal creatinine range to be getting on these tests, or is even a variation of this degree in his tests a sign that he's still cheating? He admitted with the low numbers - the 20s and 30s - that he sometimes drinks 2 bottles of water before testing.

And yes, he is absolutely a chronic alcoholic. There is a psychological evaluation that calls him a "catastrophic" alcoholic. Also, does alcoholism contribute to asthma? Because he has a bout with asthma approximately once a year, or so he says. Alternatively, could drinking that much water contribute to asthma?

The court won't let us do breathalyzer tests for him, unfortunately, but I agree that would be the best method. Is there any other kind of test you are aware of that might not be as easy to adulterate as the urine EtG? I've heard there might be hair tests that are reliable.

And thank you for the advice! I'm glad to have a place to learn about these things. I really appreciate your time and your expert advice. You have been a big help already.