Blood Urea Nitrogen (BUN)

CPT: 84520

Synonyms

Un

Blood urea nitrogen

BUN

 

Expected Turnaround Time

24 Hours

Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.

Specimen Requirements

Specimen

Serum, Plasma

Volume

5 ml

Minimum Volume

7 ul

Container

SST (Serum), Red Top (Separate Serum), Lithium Heparin (Plasma)

Storage Instructions

Room Temp., Refrigerated (2-8 C)

Stability Requirements

Room temp. 7 days, Refrigerated 7 days

Causes for Rejection

Mislabeled specimen, grossly hemolyzed specimen, sample collected expired tubes, clotted specimen

Test Details

Use

This test is use in the quantitative determination of urea nitrogen (an end product of nitrogen metabolism) in human serum, plasma (lithium heparin), and urine

Methodology

Enzymatic (Urease)

Reference Interval

9-23 mg/dL.

Additional Information

Blood Urea Nitrogen (BUN) is a commonly used clinical parameter that reflects renal function and protein metabolism. Urea, the primary end-product of protein catabolism, is synthesized in the liver and excreted by the kidneys; therefore, BUN levels can be influenced by renal perfusion, liver function, and protein intake or catabolism. Elevated BUN may indicate impaired kidney function, dehydration, or increased protein breakdown, whereas low levels are often associated with liver disease or malnutrition. BUN is most informative when interpreted in conjunction with serum creatinine to assess renal function and differentiate causes of azotemia.

References:

  • Choe, H., Yoon, S. Y., Kim, J. Y., & Kim, H. (2020). Clinical usefulness of blood urea nitrogen/creatinine ratio in patients with suspected volume depletion or prerenal azotemia. The American Journal of Emergency Medicine, 38(1), 79–83. https://doi.org/10.1016/j.ajem.2019.02.030

  • Juraschek, S. P., Selvin, E., Folsom, A. R., Coresh, J., & Matsushita, K. (2013). Plasma urea nitrogen and risk of incident diabetes mellitus. The Journal of Clinical Endocrinology & Metabolism, 98(2), 989–995. https://doi.org/10.1210/jc.2012-3235

Footnotes

Statement on Medical Necessity
All ordered tests should be medically necessary for the diagnosis or detection of disease, illness, impairment, symptom, syndrome, or disorder and the results should be used in the medical management and treatment decisions for the patient. Solaris requires ICD-10 codes with each order for lab testing and both the tests ordered and the diagnosis should be documented in the provider’s medical record for the patient. The United States Department of Health and Human Services, Office of Inspector General, takes the position that a provider who orders medically unnecessary tests may be subject to civil penalties.

Panels and Profiles
Solaris offers Providers the convenience of ordering test combinations in a group at times with the flexibility to choose appropriate test(s) for individual patients. Providers should only order those tests that he or she believes are medically necessary for each patient, and a lesser inclusive profile or individual tests should be ordered if not all tests in the test combination/profile are medically necessary. All tests offered in a test combination/profile may be ordered separately as individual tests. Solaris encourages clients to contact their Solaris representative if the testing configurations shown do not meet individual needs for any reason, or if some other combination of procedures is needed.

CPT Codes
CPT Codes listed are in accordance with Current Procedural Terminology, a publication of the American Medical Association. CPT codes are the responsibility of the billing party and are listed here for informational purposes. Correct coding may vary from one carrier to another. Solaris may bill specific carriers using codes other than what is shown.

Questions?

For questions or inquiries related to testing please reach out to
customerservice@solarisdx.com or contact us by phone at (844) 550-0308.