What Does Creatinine Level Mean for Kidney Function?

Creatinine is a waste product that your body makes naturally as muscles use energy. It is carried through your bloodstream to the kidneys, where it is filtered out and removed through urine. Because of this, creatinine levels in the blood are a useful way to measure how well your kidneys are working.

When the kidneys are functioning normally, they keep creatinine levels within a healthy range. If kidney function starts to slow down, creatinine builds up in the blood because the kidneys are not filtering it as efficiently. That is why higher-than-normal creatinine levels may suggest reduced kidney function.

The exact range for normal creatinine can vary slightly between labs, but for most adults, it falls around:

• 0.6 to 1.2 mg/dL (milligrams per deciliter) in men
• 0.5 to 1.1 mg/dL in women

Factors like age, sex, muscle mass, and diet can affect your creatinine level. For example, people with more muscle may naturally have higher levels, while older adults or those with less muscle might have lower levels even with reduced kidney function.

To get a clearer picture, doctors often use your creatinine level to calculate your estimated glomerular filtration rate (eGFR). This provides a more complete view of how well your kidneys are filtering blood. eGFR takes into account age, sex, and other factors alongside the creatinine result.

It is important to note that a single high reading does not always mean there is a serious problem. Temporary changes can happen due to dehydration, certain medications, or intense exercise. However, consistently elevated creatinine levels may point to chronic kidney issues that require medical attention.

Understanding your creatinine level gives you and your doctor important information about your kidney health—even before symptoms appear.

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