BUN

Question 1

Urea is the principle waste product of __________

Answer 1

protein catabolism

Question 2

Urea is synthesized in the ____ from ammonia which is produced as a result of the deamination of amino acids.

Answer 2

liver

Question 3

urea nitrogen in the blood comprises only about ____ of the non-protein nitrogen.

Answer 3

45%

Question 4

importance of urea nitrogen determination is its value as an indicator of ______ and _______ functions.

Answer 4

liver and kidney

Question 5

Decreases in Blood Urea Nitrogen (BUN) are seen with ____.

NAAP

Answer 5

nephritis
acute liver destruction
amyloidosis
pregnancy.

Question 6

Increases in BUN are encountered with

MACAU PIPS

Answer 6

Metallic poisoning
Acute and chronic nephritis
Cardiac failure
Addison’s Disease
Uremia
pneumonia
intestinal and urinary obstruction
peritonitis
surgical shock

Question 7

The Stanbio BUN procedure is a modification of the method described by _______

Answer 7

Sampson

Question 8

Urea is catalytically converted to __________ by the use of urease.

Answer 8

ammonium carbonate

Question 9

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.

Answer 9

NADH to NAD

Question 10

Reagent preparation: Working reagent

Answer 10

5 parts of buffer
1 part enzyme

Question 11

BUN Enzyme

Answer 11

NADH (Disodium salt)

Question 12

Reagents should appear _____.

Answer 12

clear and colorless.

Question 13

The Working Reagent is stable for_______ at 2-8°C or _____ at room temperature (15
25°C).

Answer 13

4 weeks; 5 days

Question 14

absorbance reading of the spectro used

Answer 14

340 nm

Question 15

specimen of choice

Answer 15

Non-hemolyzed serum

Question 16

Anticoagulants containing _______ or _____ must be avoided

Answer 16

ammonium; fluoride salts

Question 17

Urea in serum is stable for up to

Answer 17

24 hours - room temp (15 to 25°C)
several days - 2-8°C
2-3 months - frozen (-20°C)

Question 18

no interference

Answer 18

Bilirubin = 40 mg/dL
Hemoglobin = 200mg/dL
Triglyceride = 2000 mg/dL

Question 19

Interfering Substances

Answer 19

hemolysis
fluoride at elevated concentration
ammonia

Question 20

Manual Procedure

Answer 20

1. Prepare BUN Working Reagent according to instructions.
2. Zero spectrophotometer at 340 nm with distilled water.
3. For each sample and control, add 1.0 mL Working Reagent to cuvet or
   test tube and warm to 37°C for 3 minutes.
4. Add 10 µL (0.010 mL) serum to its respective tube and mix gently.
5. After exactly 30 seconds read and record absorbance (A1).
6. At exactly 60 seconds after reading (A1), read and record absorbance (A2).
7. Calculate the change in absorbance (∆A) by subtracting (A1-A2).
8. Run patients and controls by following steps 4 through 7.

Question 21

formula

Answer 21

Serum BUN (mg/dL) = Au/ As x30

Question 22

Normal Range

Answer 22

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