Creatinine
Creatinine is a waste product from the muscles that the kidneys filter out of the blood.
Creatinine is a waste product formed when the muscles use energy. It is filtered out of the blood by the kidneys, so the level relates to both muscle mass and kidney filtration. It is also used to calculate eGFR.
Muscle mass has a large effect, so people with more muscle usually have higher creatinine. Eating a lot of meat shortly before the test, creatine supplements, hard training and drinking too little raise the level for a while. Some medicines also affect it.
Foods that help
Enough water through the day, vegetables, fruit and berries, and a balanced amount of protein from fish, eggs, dairy and legumes.
Foods to limit
A large meat meal the evening before the test, creatine supplements before the test, and a lot of salt and processed food.
Track it through the year
One value is a snapshot. Following it up shows whether what you changed is working.
Related markers
Educational information only — not a diagnosis. Every result is checked against safe limits, and anything critical is escalated for follow-up.
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