Blood Urea Nitrogen

Question 1

Reference method:

Answer 1

isotope dilution mass spectrometry

Question 2

Routine method:

Answer 2

Indirect/coupled enzymatic method

Question 3

Measurement principle:

Answer 3

Indirect/coupled enzymatic method

Question 4

Reagents

Reagent 1:
Reagent 2:

Standard

Answer 4

Reagent 1:
 2 enzymes (urease and glutamate dehydrogenase)
 a - ketoglutarate
 Buffer
Reagent 2:
 NADH

Question 5

1st step involves the catalysis of urea by _____, forming _____ and _______ molecules

Answer 5

urease
ammonia
carbon dioxide

      Urease Urea -----------> NH3 + CO2

Question 6

The final step involves the reaction of ____ with ____ and ________, which, jn the presence of _________, leads to catalysis and formation of ______, _____, and ______

Answer 6

ammonia
NADH
a-ketoglutarate
glutamate dehydrogenase
L-glutamate, NAD, H20

Question 7

______ will detect the decrease in the NADH molecules due to successive catalytic reaction

Answer 7

Spectrophotometer

Question 8

Decrease in NADH molecule leads to _______ of light by the sample

Answer 8

decrease absorbance

Question 9

Therefore, decrease in absorbance means _______present in the sample.

Answer 9

increase of urea

Question 10

Normal Values 
                            Urea         BUN
Newborn
 <6 mons:
 > 7 mons:

Adult
<65 yrs:
> 65 yrs:

Answer 10

UREA BUN
Newborn
<6 mons: <42 <19.6
> 7 mons: <48 <22.4

Adult
<65 yrs: <50 <23.3
> 65 yrs: <71 <33.1

Question 11

Assay procedure:

Wavelength:
Temperature:
Measurement:

Answer 11

Wavelength: 340 nm
Temperature: 37C
Measurement:: against water

Question 12

Mix reagent 1 and reagent 2 with a ration of ____

Answer 12

5:1

Question 13

Mix well, then read off absorbance (A1) after _____ at ___. Read off absorbance once again after ______ (A2)

Answer 13

60 seconds
37C
2 mins

Question 14

Computation:

Answer 14

SA sample = A sample (1st) - A sample (2nd)
SA Standard = A standard (1st) - A standard (2nd)

50 x SA sample/SA standard