What this marker measures
Creatinine alone does not fully capture kidney function; the eGFR (estimated glomerular filtration rate) is calculated from creatinine alongside age, sex, and ethnicity to give a more complete picture.
High or low: what it can mean
High Creatinine
A higher-than-normal creatinine suggests the kidneys may not be filtering as efficiently as usual. This can occur with dehydration, strenuous exercise, high protein intake, or kidney function changes. Context and trends over time matter greatly.
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Low Creatinine
Low creatinine can reflect reduced muscle mass — common in elderly individuals, people with low muscle bulk, or during pregnancy.
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Lifestyle considerations
- •Staying well-hydrated helps the kidneys filter waste efficiently
- •Extremely high protein intake can temporarily raise creatinine levels
Frequently asked questions
What is Creatinine?
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Creatinine is a waste product from normal muscle metabolism, filtered by the kidneys and excreted in urine. Blood creatinine levels reflect how well the kidneys are filtering waste.
What does Creatinine measure?
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Creatinine alone does not fully capture kidney function; the eGFR (estimated glomerular filtration rate) is calculated from creatinine alongside age, sex, and ethnicity to give a more complete picture.
What does high Creatinine mean?
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A higher-than-normal creatinine suggests the kidneys may not be filtering as efficiently as usual. This can occur with dehydration, strenuous exercise, high protein intake, or kidney function changes. Context and trends over time matter greatly.
What does low Creatinine mean?
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Low creatinine can reflect reduced muscle mass — common in elderly individuals, people with low muscle bulk, or during pregnancy.
What supports healthy Creatinine levels?
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Staying well-hydrated helps the kidneys filter waste efficiently. Extremely high protein intake can temporarily raise creatinine levels
Related biomarkers
Editorial note
LabTestly explains lab markers using plain-English educational content. Reference ranges may vary by laboratory and should be interpreted with a clinician.
Educational content · Editorially reviewed for clarity · Last updated
Common sources used for lab-test education
Not medical advice
This page is for general understanding only and does not replace medical advice from your clinician. Reference ranges can vary by laboratory, age, sex, pregnancy status, medications, and clinical context.