Creatinine and Urea

Creatinine is the final metabolite of creatine involved in muscle energy metabolism. It is produced continuously in muscle tissue and excreted by the kidneys in urine. Blood creatinine level reflects kidney function — their ability to filter and remove metabolic waste. Elevated creatinine indicates reduced kidney function, which may be caused by acute or chronic kidney diseases, dehydration, muscle injury, or certain medications. Low levels are rare and usually not clinically significant. Urea is the primary breakdown product of proteins and amino acids in the body. It is formed in the liver and also excreted by the kidneys. Blood urea levels depend on protein metabolism intensity, kidney function, and hydration status. Elevated urea (azotemia) can occur with kidney failure, dehydration, bleeding, intense physical activity, or high protein intake. Low urea levels are usually associated with impaired protein synthesis, liver diseases, or pregnancy. Reasons for conducting creatinine and urea tests:

• Assessment of kidney function and filtration capacity
• Diagnosis and monitoring of kidney diseases such as glomerulonephritis, pyelonephritis, renal failure
• Evaluation of body hydration status
• Monitoring therapy in chronic kidney diseases

How the test is done:

• Blood is drawn from a vein, preferably fasting, in the morning
• Avoid intense physical activity and excessive protein intake before the test

Important to know:

• Results should be interpreted together with other indicators (e.g., glomerular filtration rate, electrolyte levels)
• Elevated creatinine and urea require further investigation to determine the cause
• In suspected kidney diseases, extended testing may be prescribed