Sorted By Test Name - Mayo Medical Laboratories

UEBF
81834
BWOR
82840
urinary tract, such as stones, enlarged prostate gland, tumors).
Useful For: The determination of serum BUN currently is the most widely used screening test for the
evaluation of kidney function. The test is frequently requested along with the serum creatinine test since
simultaneous determination of these two compounds appears to aid in the differential diagnosis of
prerenal, renal and postrenal hyperuremia.
Interpretation: Serum BUN determinations are considerably less sensitive than BUN clearance (and
creatinine clearance) tests, and levels may not be abnormal until the BUN clearance has diminished to less
than 50%. Clinicians frequently calculate a convenient relationship, the urea nitrogen/creatinine ratio:
serum bun in mg/dL/serum creatinine in mg/dL. For a normal individual on a normal diet, the reference
interval for the ratio ranges between 12 and 20, with most individuals being between 12 and 16.
Significantly lower ratios denote acute tubular necrosis, low protein intake, starvation or severe liver
disease. High ratios with normal creatinine levels may be noted with catabolic states of tissue breakdown,
prerenal azotemia, high protein intake, etc. High ratios associated with high creatinine concentrations may
denote either postrenal obstruction or prerenal azotemia superimposed on renal disease. Because of the
variability of both the BUN and creatinine assays, the ratio is only a rough guide to the nature of the
underlying abnormality. Its magnitude is not tightly regulated in health or disease and should not be
considered an exact quantity.
Reference Values:
Males
1-17 years: 7-20 mg/dL
> or =18 years: 8-24 mg/dL
Reference values have not been established for patients that are less than 12 months of age.
Females
1-17 years: 7-20 mg/dL
> or =18 years: 6-21 mg/dL
Reference values have not been established for patients that are less than 12 months of age.
Clinical References: Tietz Textbook of Clinical Chemistry. 4th edition. Edited by C. Burtis, E.
Ashwood, and D. Bruns. WB Saunders Company, Philadelphia, 2006; 24:801-803.
Blood Urea Nitrogen, Body Fluid
Clinical Information: Not available
Useful For: Not established
Interpretation: None available
Reference Values:
Not applicable
Clinical References: Tietz Textbook of Clinical Chemistry. Edited by Burtis and Ashwood.
Philadelphia, WB Saunders Co, 1994
Blood Worm, IgE
Clinical Information: Clinical manifestations of immediate hypersensitivity (allergic) diseases are
caused by the release of proinflammatory mediators (histamine, leukotrienes, and prostaglandins) from
immunoglobulin E (IgE)-sensitized effector cells (mast cells and basophils) when cell-bound IgE
antibodies interact with allergen. In vitro serum testing for IgE antibodies provides an indication of the
immune response to allergen(s) that may be associated with allergic disease. The allergens chosen for
testing often depend upon the age of the patient, history of allergen exposure, season of the year, and
clinical manifestations. In individuals predisposed to develop allergic disease(s), the sequence of
sensitization and clinical manifestations proceed as follows: eczema and respiratory disease (rhinitis and
bronchospasm) in infants and children less than 5 years due to food sensitivity (milk, egg, soy, and wheat
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