Your serum (blood) creatinine level is a very effective test for checking your kidney health. However, there may be other factors that can cause higher or lower creatinine levels in your blood that are not related to your kidney health. In other words, your actual kidney function (eGFR level) may be higher or lower than what is reported in your lab results.
Some factors that can lead to higher creatinine levels (making your eGFR level appear lower than it might really be) include:
- Eating large amounts of cooked meats
- Taking creatine supplements
- Recent high intensity exercise
- High muscle mass (very muscular body frame, bodybuilder)
- Taking medications such as cimetidine, cobicistat, dolutegravir, fenofibrate, ritonavir, or trimethoprim
Some factors that can lead to lower creatinine levels (making your eGFR level appear higher than it might really be) include:
- Following a vegan or vegetarian diet
- Low muscle mass
- History of an amputation or muscle wasting disease
- Severe liver disease (cirrhosis)
The actual effect that these factors may have on a person’s serum (blood) creatinine level is highly variable. In other words, everyone responds very differently to these factors. So, it is very important to talk with your healthcare professional if you have concerns about interpreting your serum (blood) creatinine or eGFR level.
Questions for your healthcare team
- When was the last time I had a serum (blood) creatinine test completed?
- What is my eGFR level based off my most recent serum (blood) creatinine level?
- When should my serum (blood) creatinine be checked again?
- Do I have any factors that might make my creatinine levels higher or lower than expected? What does this mean for how I should interpret my eGFR (kidney function) test?