Kidneys, electrolytes and minerals
Creatinine blood test: what a high or low result means
What a creatinine blood test measures, what high or low creatinine can mean, and what to ask your doctor.
Got your creatinine result in front of you?
Paste your whole results sheet (or upload a photo, PDF or Word file) and Patiently AI explains it in plain English, sticking to the numbers and ranges on your report. Free, no account, and identifying details are removed on your device first.
Explain my results → Available on web, iOS & Android.What is creatinine?
Creatinine is a waste product made by your muscles as they work. Your kidneys filter it out of your blood and into your urine, so the level in your blood is a useful guide to how well your kidneys are working. Creatinine is part of a kidney blood test called U&E (urea and electrolytes), or a metabolic panel in the US, and it is used to calculate your eGFR.
Why is this test done?
- To check kidney function
- To monitor diabetes, high blood pressure and kidney disease
- Before and during treatment with medicines that affect or are cleared by the kidneys
- When someone is unwell or dehydrated
What does a high creatinine mean?
A high creatinine can mean your kidneys are filtering less well, either for a short time or over the long term.
Possible reasons include:
- Dehydration
- Kidney disease, short-term or long-term
- Some medicines, such as anti-inflammatory painkillers and some blood pressure medicines
- A blockage to the flow of urine, for example from an enlarged prostate
- High muscle mass, creatine supplements or eating a lot of cooked meat before the test
What does a low creatinine mean?
A low creatinine is rarely a problem. It usually reflects lower muscle mass.
Possible reasons include:
- Low muscle mass, for example in older or frail people
- Pregnancy
- Malnutrition
Why we don't list a "normal range". Reference ranges differ between laboratories and can depend on your age, sex and whether you are pregnant. The range printed next to your result on your own report is the one that applies to you, so use that, and talk to your doctor about what your result means for you.
What can affect your creatinine result?
- Muscle mass
- Eating cooked meat in the hours before the test
- Creatine supplements
- Hard exercise
- Dehydration
Make sense of the whole report, not just one line
Results are easier to understand together. Patiently AI explains your report as a whole and writes personalised questions for your next appointment.
Try it with your own results → Paste, upload or photograph your results.Questions to ask your doctor
- Is my creatinine higher than my previous results?
- What is my eGFR, and is my kidney function stable?
- Could dehydration or a medicine explain the result?
- Should I have a repeat test?
Frequently asked questions
Can drinking more water lower creatinine?
If your creatinine is raised because you were dehydrated, drinking enough fluid can bring it back down. It will not change creatinine that is raised because of kidney disease.
Why does muscle affect creatinine?
Creatinine comes from muscle, so people with more muscle make more of it. That is why a bodybuilder may have a higher result with perfectly healthy kidneys.
Is creatinine the same as creatine?
No, but they are related. Creatine is a substance used by muscles for energy, and creatinine is the waste product it breaks down into. Creatine supplements can raise creatinine.
Can Patiently AI explain my creatinine result?
Yes. Paste your results, or upload a photo, PDF or Word file, and Patiently AI explains them in plain English, sticking to the numbers and ranges on your own report rather than adding its own, and suggests questions to ask your doctor. It is free, needs no account, and removes identifying details on your device first.