UREA AND CREATININE

Question 1

= measures Blood Urea Nitrogen

Answer 1

INDIRECT METHOD / ENZYMATIC

Question 2

Based on the preliminary hydrolysis of urea with urease followed by some process that quantitates the ammonium ion

Answer 2

INDIRECT METHOD / ENZYMATIC

Question 3

INDIRECT METHOD / ENZYMATIC OF UREA DETERMINATION

Answer 3

1. Berthelot reaction
2. Nessler’s Reaction
3. GLDH-coupled enzymatic method
4. Conductimetric method
5. Urograph or Urastrat strip
6. Indicator dye (uriol)

Question 4

Dupont ACA Analyzer

Answer 4

3. GLDH-coupled enzymatic method

Question 5

Beckman BUN Analyzer

Answer 5

4. Conductimetric method

Question 6

Kodak Ectachem Analyzer

Answer 6

6. Indicator dye (uriol)

Question 7

Decrease in absorbance of NAD at 340 nm

Answer 7

GLDH-coupled enzymatic method

Question 8

Based on the measurement of the conductivity generated from the reaction of urease on urea producing ammonium ions & bicarbonates

Answer 8

Conductimetric method

Question 9

Urograph or Urastrat strip Chemical principle:

Answer 9

Conway Microdiffusion method

Question 10

Urograph or Urastrat strip Physical principle:

Answer 10

based on chromatography

Question 11

Dye is added to NH4 ions from urea hydrolysis & the color change is measured

Answer 11

Indicator dye (uriol)

Question 12

Used in multilayer film reagents, dry reagent strips and automated systems

Answer 12

Indicator dye (uriol)

Question 13

DIRECT METHODS OF UREA DETERMINATION

Answer 13

1. Diacetyl Monoxime
2. ortho –phthaldehyde

Question 14

Fearon

Answer 14

Diacetyl Monoxime

Question 15

Direct condensation reaction

Answer 15

Diacetyl Monoxime

Question 16

very toxic

Answer 16

Diacetyl

Question 17

: adapted by automated methods

Answer 17

ortho – phthaldehyde

Question 18

Urea + OP —>

Answer 18

Isoindoline

Question 19

Isoindoline + [?] —-> colored compound

Answer 19

Naphthylethylenediamine

Question 20

DIRECT METHOD OF CREATININE DETERMINATION

Answer 20

JAFFE REACTION

Question 21

INDIRECT / ENZYMATIC METHODS OF CREATININE DETERMINATION

Answer 21

F. Lim – Creatininase or creatinine iminohydrolase
G.A. Moss – Creatinine Amidohydrolase

Question 22

Creatinine reacts with alkaline picrate at two different pH levels

Answer 22

Yatzidis method

Question 23

: protein & other interfering materials will reacts w/ picrate but creatinine does not

Answer 23

pH 10

Question 24

: both creatinine & proteins react

Answer 24

pH 11

Question 25

Sources of error :

Answer 25

1. ascorbate, glucose, alpha keto acids and uric acid – false increase 2. drugs : cephalosporin and dopamine intake – false increase : lidocaine intake – false increase

Question 26

Creatinine + alkaline picrate ----->

Answer 26

Creatinine picrate (red orange/yellow) 510 nm

Question 27

Alkaline picrate: 1 part [?] and 5 parts [?] (2,4,6 trinitrophenol)

Answer 27

10% NaOH sat. picric acid

Question 28

lacks specificity

Answer 28

Jaffe reaction

Question 29

Non-creatinine Jaffe-reacting chromogens:

Answer 29

- Proteins - Glucose - Ascorbic acid - Guanidine - Acetone - Cephalosporins - α-ketoacids (acetoacetate and pyruvate)