A Creatinine Blood Test measures the level of creatinine in the blood. Creatinine is a waste product generated from the normal breakdown of muscle tissue during physical activity. It is produced at a fairly constant rate and is filtered out of the blood by the kidneys and excreted in urine.
This test is widely used to evaluate kidney function. Since the kidneys are responsible for filtering creatinine, elevated levels in the blood usually indicate that the kidneys are not functioning properly. It is often ordered alongside a BUN (Blood Urea Nitrogen) test and used to calculate eGFR (estimated Glomerular Filtration Rate), which provides a more precise measure of kidney function. It helps diagnose conditions such as chronic kidney disease, acute kidney injury, and kidney infections.
