BUN Flashcards
Urea is the principle waste product of __________
protein catabolism
Urea is synthesized in the ____ from ammonia which is produced as a result of the deamination of amino acids.
liver
urea nitrogen in the blood comprises only about ____ of the non-protein nitrogen.
45%
importance of urea nitrogen determination is its value as an indicator of ______ and _______ functions.
liver and kidney
Decreases in Blood Urea Nitrogen (BUN) are seen with ____.
NAAP
nephritis
acute liver destruction
amyloidosis
pregnancy.
Increases in BUN are encountered with
MACAU PIPS
Metallic poisoning
Acute and chronic nephritis
Cardiac failure
Addison’s Disease
Uremia
pneumonia
intestinal and urinary obstruction
peritonitis
surgical shock
The Stanbio BUN procedure is a modification of the method described by _______
Sampson
Urea is catalytically converted to __________ by the use of urease.
ammonium carbonate
The reaction rate is dependent upon the concentration of the influence of glutamic dehydrogenase. The rate of this second reaction is dependent upon the first and can be measured by the rate of conversion of
_________ by the change of absorbancy at 340 nm.
NADH to NAD
Reagent preparation: Working reagent
5 parts of buffer
1 part enzyme
BUN Enzyme
NADH (Disodium salt)
Reagents should appear _____.
clear and colorless.
The Working Reagent is stable for_______ at 2-8°C or _____ at room temperature (15
25°C).
4 weeks; 5 days
absorbance reading of the spectro used
340 nm
specimen of choice
Non-hemolyzed serum
Anticoagulants containing _______ or _____ must be avoided
ammonium; fluoride salts
Urea in serum is stable for up to
24 hours - room temp (15 to 25°C)
several days - 2-8°C
2-3 months - frozen (-20°C)
no interference
Bilirubin = 40 mg/dL
Hemoglobin = 200mg/dL
Triglyceride = 2000 mg/dL
Interfering Substances
hemolysis
fluoride at elevated concentration
ammonia
Manual Procedure
- Prepare BUN Working Reagent according to instructions.
- Zero spectrophotometer at 340 nm with distilled water.
- For each sample and control, add 1.0 mL Working Reagent to cuvet or
test tube and warm to 37°C for 3 minutes. - Add 10 µL (0.010 mL) serum to its respective tube and mix gently.
- After exactly 30 seconds read and record absorbance (A1).
- At exactly 60 seconds after reading (A1), read and record absorbance (A2).
- Calculate the change in absorbance (∆A) by subtracting (A1-A2).
- Run patients and controls by following steps 4 through 7.
formula
Serum BUN (mg/dL) = Au/ As x30
Normal Range
BUN = 8 - 23 mg/dL
Urea = 17 - 49 mg/dL
Urea (mg/dL) = BUN (mg/dL) x 2.14
Urea (mmol/L) = Urea(mg/dL) x 0.167
