Creatinine Test: A Key Marker of Kidney Function
Creatinine is a waste product from normal muscle activity that the kidneys filter out of the blood. A blood creatinine test helps estimate kidney function, often through a calculation called eGFR. Creatinine can also be measured in urine, sometimes as a ratio with albumin or protein, which helps evaluate how much protein is being lost. Muscle mass, diet, and hydration can influence creatinine levels, so a single abnormal result is usually interpreted alongside other tests and clinical history.
Key Takeaways
- Creatinine is a waste product from muscle activity that the kidneys filter out.
- A blood creatinine test helps estimate kidney function, often through eGFR.
- Urine creatinine can be measured, sometimes as a ratio with albumin or protein.
- Muscle mass, diet, and hydration can influence creatinine levels.
- A single abnormal result is usually interpreted alongside other tests and clinical history.
Frequently Asked Questions
What does high creatinine mean?
It can mean reduced kidney function, but dehydration, high muscle mass, and some medications also affect it. A clinician interprets the value in context.
Do I need to fast for a creatinine test?
Fasting is usually not required.
Can I order a creatinine test directly?
Yes, creatinine is included in many direct-access panels.
Can creatinine be measured in urine?
Yes. A urine creatinine test, or a ratio with albumin or protein, is used for specific evaluations.
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