Test Code: 4505CPT: 84520
|Use||The blood urea nitrogen or BUN test is primarily used, along with the creatinine test, to evaluate kidney function, help diagnose kidney disease, and to monitor people with acute or chronic kidney dysfunction or failure. Measurements of urea nitrogen can also be used in the diagnosis and treatment of metabolic disorders. Measurement of creatinine allows for the urea nitrogen/creatinine ratio, which is often used for diagnosis. 2|
|Clinical Utility||Urea is a waste product formed in the liver when protein is metabolized. Urea is released by the liver into the blood and is carried to the kidneys, where it is filtered out of the blood and released into the urine. Since this is an ongoing process, there is usually a small but stable amount of urea nitrogen in the blood. However, when the kidneys cannot filter wastes out of the blood due to disease or damage, then the level of urea in the blood will rise.
Low BUN levels are not common and are not usually a cause for concern. They may be seen in severe liver disease, malnutrition, and sometimes when a person is overhydrated (too much fluid volume), but the BUN test is not usually used to diagnose or monitor these conditions. It is also normal during pregnancy.
Increased BUN levels suggest impaired kidney function. This may be due to acute or chronic kidney disease, damage, or failure. It may also be due to a condition that results in decreased blood flow to the kidneys, such as congestive heart failure, shock, stress, recent heart attack, or severe burns, to conditions that cause obstruction of urine flow, or to dehydration.
|Intended Patient Population||18+ and Older Adult Males & Females|
|Patient Preparation||None Specified|
|Tube||Red, Green, Tiger|
|Volume||4mL Whole Blood (1mL Serum/Plasma)|
|Min Sample Volume||0.1 mLs|
|Reference Ranges||M & F ≥ 18 yrs old; 7-25 mg/dL|
|Analytical Measurement Range||5-150 mg/dL|
|Critical Values||≥65.0 mg/dL|
|Test Methodology||Quantitative Spectrophotometry|
|Test Turnaround Time||1 Day|
|Limitations||Interpretation requires clinical information and the other electrolytes.|
|Specimen Stability||7 Days RT
7 Days RF
|Laboratory Developed Test (LDT)||Yes|