Kidney
Creatinine
What it is
Creatinine is a waste product of normal muscle metabolism that the kidneys filter out. Its blood level, together with age and sex, is used to calculate eGFR (estimated kidney filtering rate).
Why it matters
A rising creatinine can indicate reduced kidney filtering. Because it comes from muscle, factors like muscle mass, a very high-protein meal or dehydration can influence it, so it is read alongside eGFR and trends.
What “optimal” looks like
A healthy range applies and differs by sex and body composition. Single readings fluctuate with hydration and diet; clinicians rely on eGFR and change over time.
This is general information, not medical advice or a diagnosis. Always discuss your results with a qualified clinician.
Related
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