Even though increased protein levels in a person’s diet can cause their blood urea nitrogen levels to increase, elevated BUN may suggest kidney involvement due to lupus or another condition such as dehydration that causes decreased blood flow to the kidneys. To evaluate an individual’s BUN level, blood is drawn from the vein, and the concentration of urea nitrogen in the blood is evaluated and compared to a standard value for that person’s age range. From the liver, urea travels in your blood to the kidneys, which filter the urea and flush it from your body in the form of urine. The liver produces nitrogen in the form of ammonia (NH3) as it breaks down proteins into their constituent amino acids. Blood urea nitrogen (BUN): The BUN test measures the amount of urea nitrogen in your blood.The eGFR is an educated estimate of the amount of blood that is filtered per minute by your glomeruli and is often used to detect kidney damage. Glomeruli are tiny ball-shaped structures in your kidneys that help filter blood and prevent the loss of valuable substances, such as blood cells and proteins. Your serum (blood) creatinine level can also be combined with your age, weight, and gender to evaluate your estimated glomerular filtration rate (eGFR). In addition, since creatinine is usually removed from the blood at a constant rate, blood creatinine levels can be used as a standard by which doctors can compare other urine or blood tests. The combination of blood and urine samples can be used to evaluate a creatine clearance-how effectively your kidneys filter small molecules, such as creatinine, from your blood. Sometimes individuals are asked to provide a 24-hour urine sample for further assessment.Other conditions, such as high blood pressure or diabetes, can also cause elevated creatinine levels. Increased blood creatinine levels may indicate an increase in lupus involvement of the kidney. Creatinine levels are measured by taking a sample of blood from your vein then, the concentration of creatinine in your blood is compared to a standard amount for your age and sex. Creatinine is formed at a constant rate in the body and excreted by the kidneys, so by evaluating the amount of creatinine in your blood, your doctor can determine how efficiently your kidneys are working.

Creatinine: Creatinine is produced by your muscles as they breakdown creatine, a substance involved in muscle contraction.The creatinine blood test and blood urea nitrogen (BUN) test are used to assess kidney function in people with lupus kidney disease (nephritis).

Your doctor will counsel you regarding the results of your personal blood work and laboratory tests. The information below is meant to provide an overview of these tests. Usually, it consists of about 7-25 tests. A blood chemistry panel is another common test used to evaluate a variety of components.

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