Blood Urea Nitrogen
(BUN)

Sample type:

Plasma or Serum (Plasma EDTA is preferred specimen type)

Uses:

Precaution:

After collection, gently invert tube 8-10 times.
Specimen should be processed within 2 hours.
Plasma: Centrifuge after collection.
Serum: Allow blood to clot for 30 minutes in a vertical position and centrifuge within 2 hours.
you should tell your doctor about any prescription drugs, over-the-counter medications, and/or dietary supplements that you usually take. Some of these can affect a BUN test.

Interference:

Results increased in: febrile illness, high protein diet, alimentary tube feeding, gastrointestinal bleeding, dehydrated patients.
Results decreased in: low protein diet, high carbohydrate diet, overhydrated patients.
Women and children tend to have lower BUN levels than men.
Advanced pregnancy may cause increased levels as a result of high protein metabolism.
Drugs that may cause increased BUN levels include: allopurinol, aminoglycosides, cephalosporins, chloral hydrate, cisplatin, furosemide, guanethidine, indomethacin, methotrexate, methyldopa nephrotoxic drugs (e.g., aspirin, amphotericin B, bacitracin, carbamazepine, colistin, gentamicin, methicillin, neomycin, penicillamine, polymyxin B, probenecid, vancomycin), propranolol, rifampin, spironolactone tetracyclines, thiazide diuretics, and triamterene.
Drugs that may cause decreased levels include: chloramphenicol and streptomycin.

Pre-analytical errors:

Unlabeled or mislabeled specimen.

Corrective action:

You should reject it and request for another sample.

Post analytical errors:

reports were sent to the incorrect patient.

The corrective action:

communication with patient, apologising for the error, and providing him with the correct report.

Reference Range:

0 up to 3 Months: 4 – 16 mg/dL

3 Months up to 16 Years: 6 – 18 mg/dL

16 Years up to 150 Years: 8 – 20 mg/dL