BUN Flashcards
is the principle waste product of protein catabolism.
Urea
It is synthesized in the liver from __________ which is produced as a result of the deamination of amino acids.
ammonia
It is synthesized in the liver from ammonia which is produced as a result of the _____________________.
deamination of amino acids
Normally, urea nitrogen in the blood comprises only about _______ of the non-protein nitrogen.
45%
The importance of urca nitrogen detenni-nation is its value as an indicator of ________ and ________ functions.
liver and kidney
Decreases in Blood Urea Nitrogen (BUN) are seen with
nephritis
acute liver destruction
amyloidosis
pregnancy.
Increases in BUN are encountered with
acute and chronic nephritis
intestinal and urinary obstruction
uremia
metallic poisoning
pneumonia
Addison’s Disease
peritonitis
surgical shock
cardiac failure.
The Stanbio BUN procedure is a modification of the method described by
Sampson
is catalytically converted to ammonium carbonate by the use of urcase.
Urea
Urea is catalytically converted to ammonium carbonate by the use of ____
urease
The reaction rate is dependent upon the concentration of the influence of _________________
glutamic dehydrogenase
can be measured by the rate of conversion of NADH to NAD by the change of absorbancy at _______nm.
340 nm
Two enzyme in urea
Urease
Glutamic dehydrogenase
BUN Buffer
Tris
2-oxoglutarate
Monosodium salt
Urease
Glutamic dehydrogenase
BUN ENZYME COMPOSITION
Disodium salt
Reagent preparation: Before use allow to stand for at least ____ minutes at room tempsrature (15-25°C)
30 minutes
Reagent preparation: Before use allow to stand for at least 30 minutes at _____________
room tempsrature (15-25°C)
Reagent Storage and Stability: when properly stered at
2-8C
Reagent Storage and Stability: stable for 4 weeks at
2-8°C
Reagent Storage and Stability: 5 days
RT (15-25C)
Preferred specimen of choice
Non-hemolyzed serum
Anticoagulant to avoid
Ammonium
Fluoride salt
serum: stable for up to 24 hours at
room temperature (15-25°C).
Serum: several days refrigerated at
2-8°C
Serum: at least 2-3 months when
frozen
(-20°C).
No interference
Bilirubin (40mg/dl)
Hemoglobin (200mg/dl)
Triglycerides (2000mg/dl)
Working reagent (ml/ul)
1.0ml (1000ul)
Warm at
37C for 3 mins
Add ________ serum to unknown cuvette and mix
0.01ml (10 ul)
After exactly _________ read und record absorbance
30 seconds
After exactly 30 seconds read und record absorbance of
A1
Al exactly______ seconds after reacing (A,), read and record absorbance
60 sec
Al exactly 60 seconds after reacing (A,), read and record absorbance
A2
Calculate change in absorbance
A1-A2 = Au
Add _______ standard to control cuvette
0.01ml (10ul)
Serum computations
Au/A(s/c) X 30
Expected value: bun
8-23 mg/dl
Expected value: urea
17-49 mg/dl
Urea: mg/dl =
bun x 2.14
Urea : mmol/L =
Urea (mg/dl) x 0.167
Principle of BUN
Protein —> ammonia —> urea (non protein nitrogen)
Urea—> h2o —> (urease) 2NHy+ 2HO3
2- oxoglutarate + NHy+ Disodium salt
Glutamic dehydrogenase—> L- glutamate + NAD + H2O
