BLOOD UREA NITROGEN

Question 1

main waste product of nitrogencontaining chemical in the body

(approximately 80% of the nitrogen excreted)

Answer 1

Urea

Question 2

• major end product of protein (dietary) and amino acid catabolism

Answer 2

Urea

Question 3

Urea is synthesized in the_____ from CO2 and ammonia from the_____ of amino acids (Kreb’s cycle)

Answer 3

liver

deamination

Question 4

Urea is synthesized in the____ from CO2 and ammonia from the_____ of amino acids (Kreb’s cycle)

Answer 4

liver

deamination

Question 5

Protein

V

Amino acids

V

Ammonia

V

Urea

Answer 5

Proteolysis, principally enzymatic

Transamination and oxidative deamination

Enzymatic synthesis in the “urea cycle”

Question 6

Widely used as a measure of renal dysfunction but its value as a measure of____ is not plausible

Answer 6

GFR

Question 7

a) Dependent to the rate of urea production and not solely to renal function

b) Freely filtered by the glomerulus but is reabsorbed (approximately_____) in some parts of the nephron

Answer 7

40%

Question 8

INCREASED CONCENTRATION

Answer 8

Pre renal
Renal
Post renal

Question 9

DECREASED CONCENTRATION

Answer 9

Low protein intake
Severe vomiting and diarrhea
Liver disease
Pregnancy

Question 10

Why measure?
- To evaluate ____ function
- To assess____ status
- To determine___ balance
- To aid in the diagnosis of___ disease
- To verify adequacy of____

Answer 10

Renal

hydration

nitrogen

renal

dialysis

Question 11

❑Urea Nitrogen x ______ = Urea (mg/dL)

❑Urea Nitrogen (mg/dL) x_____ = Urea (mmol/L)

Answer 11

2.14

0.36

Question 12

3 Methods: (Bishop)

Answer 12

1. Conventional Method
2. Kinetic Method
3. Chemical Method

Question 13

• Gold standard; Reference method

Answer 13

Isotopic dilution mass spectrometry

Question 14

• Hydrolysis of Urea by Urease
• Quantification of NH4+

Answer 14

Conventional Method

Question 15

Conventional methods (2)

Answer 15

• Nessler’s Reaction
• Berthelot’s Reaction with Nitroprusside

Question 16

• Urease and GLDH
• Measures disappearance of NADH @ 340 nm

• Used on common automated machines
• Reference Method

Answer 16

Kinetic Method (Coupled-Enzyme)

Question 17

Kinetic Method (Coupled-Enzyme)

• Measures disappearance of______ @____

Answer 17

NADH @ 340 nm

Question 18

To produce glutamate need ng what enzyme?

Answer 18

GLDH = glutamate dehdrogenase

Question 19

Chemical Methods (2)

Answer 19

A. Diacetyl Monoxime (Direct Method)

B. o-Phthalaldehyde Method (Direct Method)

Question 20

• Urea reacts directly with diacetyl monoxime in strong acidic condition to form a yellow diazine derivative @ 540nm

Answer 20

Diacetyl Monoxime (Direct Method)

Question 21

Diacetyl Monoxime (Direct Method)

• Urea reacts directly with_____ in strong____ condition to form a_____ diazine derivative @____

Answer 21

diacetyl monoxime

acidic

yellow

540nm

Question 22

In Diacetyl Monoxime (Direct Method)

• (2) Stabilizes color;

intensifies reaction

Answer 22

Ferric iron and thiosemicarbazide

Question 23

o-Phthalaldehyde Method (Direct Method) (2)

Answer 23

• o-Phthalaldehyde
• Naphthylethylenediamine

Question 24

SPECIMEN REQUIREMENT & INTERFERING SUBSTANCES

Urine
• Should be_____ if cannot be analyzed within an hour

• UREA is susceptible to_______

Answer 24

refrigerated

bacterial decomposition