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Flashcards in Blood Urea Nitrogen Deck (21)
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0

Reaction wherein ammonium ions react with hypochlorite and salicylate to give a green dye

Modified Berthelot Reaction

1

Proportional to the urea concentration in the sample

Increase of absorbance at 578 nm

2

It is hydrolyzed in the presence of water and urease to produce ammonia and carbon dioxide

Urea

3

Contents of reagent 1

1 Phosphate buffer
2 Sodium salicylate
3 Sodium nitroprusside
4 EDTA
5 Urease

4

Contents of reagent 2

1 Phosphate buffer
2 Sodium hydroxide
3 Sodium hypochlorite

5

Contents of urea standard

1 Urea
2 BUN

6

Reagent stability

1 Expiry date (2-8 Celsius)

Reagent 1
2 6 weeks (2-8 Celsius)
3 10 days (15-25 Celsius)

Reagent 2
4 6 weeks (2-25 Celsius)

7

Serum

1 Plasma may be used except with ammonium heparin
2 Do not use lipemic sera
3 Serum or plasma can be stored for up to 3 days at 4 Celsius

8

Wavelength

590 nm

9

Optical path

1 cm

10

Temperature

1 20-25 Celsius
2 37 Celsius

11

Calculation of the urea nitrogen concentration

Serum/plasma
1 C = 80 x (sample absorbance/standard absorbance) (mg/dL)
2 C = 13.3 x (sample absorbance/standard absorbance) (mmol/L)

12

Reference range

Serum/plasma: 6-20 mg/dL or 2.1-7.1 mmol/L

13

Contents of reagent 2 that are irritants

1 Sodium hydroxide
2 Sodium hypochlorite

14

Preservative

Sodium azide

15

T or F. All anticoagulants can be used

F. Ammonium heparin cannot be used

16

T or F. The test is not influenced by hemoglobin values up to 200 mg/dL and by bilirubin values up to 10 mg/dL

T

17

Linearity

Serum/plasma: up to 400 mg/dL or 66.6 mmol/L

18

Reagent 1 procedure

Mix and incubate for 5 minutes at 20-25 Celsius or 3 minutes at 37 Celsius

19

Reagent 2 procedure

Mix, incubate for 10 minutes at 20-25 Celsius or for 5 minutes at 37 Celsius

20

Time of measurement

Within 60 minutes