Normal Creatinine Levels

Another family is asking us about their child's creatinine, and they were just told by their doctors that are taking care of their child that their child's creatinine is just a little above normal. Couple of important things about that. Um, the normal range that most labs will report is a normal range for an adult. So, when your child is younger, here at Cincinnati, we actually have um different levels of normal based on the size and age of the child, and we don't use the normal adult range as our normal for a child. OK? So, the normal adult range is um between 0.8 to 1.2 would be a normal adult range. Um, if they're using that range for a child who's less than 15 years old, I think that probably is an inaccurate representation of your child's kidney function and is actually underestimating how severely injured the kidneys might be. So that's a very, very important question to ask your providers is, are you doing a pediatric normal age range, or are you looking at an adult range for the creatinine and comparing my child's creatinine to that adult range? So please uh advocate for your child and ask that question of the uh care providers. Besides the absolute creatinine level, another thing that we would be looking at is the rate of change of the creatinine. So when the child comes back to see us, how much has the change been in the past year, uh, especially during times of stress for the body's puberty. So if the change is, you know, significant every time we're seeing the child, then we know that that child's kidneys are in danger and we really have to bring all of our forces to bear to try and protect that kidney. So absolute creatinine value, the rate of change of creatinine value, and then more importantly than the absolute creatinine value or the rate of change is what is the actual GFR, right? Because creatinine is a test that is affected by your child's hydration status. Um, if a child is undernourished and doesn't have an appropriate amount of muscle mass, that creatinine is going to be low. But it's not a normal low. It's an artificially low because the child doesn't have a normal amount of muscle. Creatinine is a protein that is made by our muscles, and it is constantly being filtered and sent out of our body by our kidneys. So as doctors who are involved in taking care of children's kidneys, we use that fact, how much of this protein is being sent out of the body on a regular basis and what is the remaining level in the body as a gauge for how well the kidneys are working. So if you have less muscle mass to begin with, your body is making less creatinine. So your level may look normal, but it's actually not. So that is an important distinction to make. Um, and we know that children with chronic kidney disease don't grow well, so that is something that we take into account every time we see them. We look at their weight, we look at their creatinine and say, is this really reflective? And there are some other additional tests that we can do to really get a better understanding of the child's real kidney function, and that would be like a GFR test or a GFR scan. So if there's any doubt about where your child's kidney health is, then you would need to have your care provider escalate the level of testing to do a GFR scan or something called a cystatin C. It's a newer test that's around. It's not as influenced by the body weight and by the hydration status of the child in terms of allowing us to calculate where your child's kidney function is. I've taught Dr. Reddy, well, well said. I'm a good student and, and, and this is, this is, this is the beauty of our team, right, that, uh, we're working so well together that we're always talking and we're learning from each other so Donna can, you know, be a master urologist because she's learned so much about pediatric urology from us. I always say I have a major in nephrology and a minor in urology. Yeah, absolutely, and I'm, I'm vice versa. So I'm a pediatric urinephrologist. Um, and, you know, the question is, should you be worried if your child's kidney function is not normal? And the answer is yes. You should be worried, um, because it needs to be investigated to say, is this change a reversible change that if it is, then we should do everything we can to reverse that change and get the kidneys as healthy as possible. If it's not a reversible change, then, as Doctor Clay mentioned, the more damaged the kidney is, the more quickly it's gonna lose its remaining function. So we really want to say, what can we do to protect the remaining function and make sure that. Your child's kidneys stay as healthy as possible for as long as possible.