Creatinine and Urea

Creatinine is the end product of creatine metabolism, which is involved in muscle energy exchange. It is produced continuously in muscle tissue and excreted by the kidneys in urine. The 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 damage, or certain medications. Low levels are rare and usually clinically insignificant.

Urea is the main product of protein and amino acid breakdown in the body. It is produced 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) may 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.

Why creatinine and urea tests are performed:

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

How the test is performed:

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

Important to know:

• Test results should always 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, an extended panel of tests may be prescribed