Chris Kresser: Creatinine when it’s mildly elevated in kids is usually not a concern. It’s something that happens if they’re still growing. You get a release of creatinine from muscle tissue that’s being broken down in the growth process. So if creatinine is just very slightly elevated, especially in a teenager who might be still growing, and there are no other markers for kidney dysfunction, it’s not typically a concern.
Another potential cause of elevated creatinine, which you’ll see if you treat patients that are really physically active and they’re doing weight lifting, is any kind of muscle or weight-bearing activity. If someone is lifting weights and tearing down muscle fibers, you can see an elevation in creatinine in that patient population. And if there are no other kidney markers, it’s usually not a concern.