BUN+Creat

Test ID: 

702804

CPT code:

82565, 84520

Synonyms:

84520: BUN

Blood Urea Nitrogen

82565: Creatinine

Clinical Use:

The BUN/Creatinine ratio is useful in the differential diagnosis of acute or chronic renal disease. Reduced renal perfusion, e.g., congestive heart failure, or recent onset of urinary tract obstruction will result in an increase in BUN/Creatinine ratio. Increased urea formation also results in an increase in the ratio, e.g., gastrointestinal bleeding, trauma, etc. When there is decreased formation of urea as seen in liver disease, there is a decrease in the BUN/Creatinine ratio. In most cases of chronic renal disease the ratio remains relatively normal.
A renal function test used in eGFR calculation.

High creatinine: Renal diseases and insufficiency with decreased glomerular filtration, urinary tract obstruction, reduced renal blood flow including congestive heart failure, shock, and dehydration; rhabdomyolysis can cause elevated serum creatinine. Low creatinine: Small stature, debilitation, decreased muscle mass; some complex cases of severe hepatic disease can cause low serum creatinine levels. In advanced liver disease, low creatinine may result from decreased hepatic production of creatinine and inadequate dietary protein as well as reduced muscle mass

Additional Test Information:

84520-Although creatinine is generally considered a more specific test to evaluate renal function, they are commonly used together. Clinical renal failure is variable between individual patients. Drug effects have been summarized

Specimen Type:

Serum (preferred) or plasma

Requested Volume: 

1 mL

Minimum Volume: 

0.5 mL

Container Type: 

Gel-barrier tube, red-top tube, green-top (heparin) tube, or lavender-top (EDTA) tube, do not use ammonia heparin tube.

Collection:

Separate serum or plasma from cells within 45 minutes of collection.

Storage Instructions:

Maintain specimen at room temperature

Stability Requirements:

Rejection Criteria

Hemolysis; improper labeling