Serum Creatinine (Creatinine Level)

Why This Test Matters

Creatinine is a byproduct of muscle metabolism and is normally filtered out of your blood by your kidneys. High levels can indicate kidney problems, while low levels might suggest muscle disorders or other health conditions. This test is often used alongside other measures, like blood urea nitrogen (BUN), to evaluate kidney function.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a larger panel. Drink plenty of water the day before to ensure your urine is diluted, but avoid excessive fluid intake on the day of testing. Inform your provider about any medications you’re taking, as some (like certain pain relievers or diuretics) may affect results.

What the Results Mean

Results are compared to a reference range based on age, sex, and body size. While exact values vary, consistently high levels may signal kidney issues, while very low levels could raise concerns about muscle metabolism or kidney function. Your healthcare provider will interpret results in the context of your overall health.

Common Causes of Abnormal Results

High creatinine levels may occur with kidney disease, dehydration, severe muscle injury, or conditions like diabetes or heart failure. Low levels might be linked to muscle wasting, liver disease, or certain genetic disorders. Always discuss results with your doctor to explore possible causes.