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Test Code BUN Blood Urea Nitrogen (BUN), LAB140


Urease with Glutamate Dehydrogenase (GLDH)

Performing Laboratory

St. Luke's Hospital Cedar Rapids

Specimen Requirements


Preferred: Green-top (lithium heparin) tube 

Acceptable: Gold-top serum gel tube, plain red-top tube, or  lavender-top (EDTA) tube

Specimen Volume: 0.1 mL of plasma or serum

Stability: Samples can be kept at 2 – 8°C and analyzed within 7 days. For longer storage,

                 samples may be frozen at -20°C or colder indefinitely.


Reference Values

7-23 mg/dL

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding


Useful For

Measurements of BUN (blood urea nitrogen) are used in the diagnosis and treatment of certain renal and metabolic diseases. Increases in serum urea nitrogen may be due to prerenal, renal or postrenal causes.