Chemical Examination of Urine

Question 1

Products of fat metabolism (ketones)

Answer 1

Acetate (2%)
Acetoacetic acid (20%)
beta-hydroxybutyric acid (78%)

Question 2

Reagent Strip for Ketones

Answer 2

Sodium nitroprusside (purple)

Question 3

Acetest

Answer 3

Tablet test for ketones;
Sodium nitroprusside
Glycine
Disodium phosphate
Lactose

Question 4

Produce an interfering red colour in alkaline test medium for ketones

Answer 4

Phenolsulfonphthalein

Bromsulphalein

Question 5

Hematuria

Answer 5

Cloudy red urine
Renal or GUT origin
Cause: Trauma
             Renal Calculi
             Glomerular diseases
             Tumors
             Pyelonephritis
             Anti-coagulant therapy

Question 6

Hemoglobinuria

Answer 6

Clear red urine
Dilute alkaline urine
Intravascular hemolysis
Causes: Hemolytic anemia
              HTR
              Severe burns
              Brown recluse spider bites
              Infections
              Strenuous exercise
Red plasma

Question 7

Large yellow-brown granules of denatured ferritin

Answer 7

hemosiderin

Question 8

Myoglobinuria

Answer 8

Clear red-brown urine
Causes: Muscle destruction (Rhabdomyolysis)
              Alcoholism
             Heroin abuse
Elevated CK, LD
Normal colour on plasma

Question 9

Reagent strip reaction on blood

Answer 9

Pseudoperoxidase activity of haemoglobin

H2O2 + tetramethylbenzidine = green blue

Question 10

False Positive Reactions (Blood)

Answer 10

Menstrual contamination
Strong oxidizing detergents
Vegetable peroxidase
Bacterial enzymes (E. coli)

Question 11

False Negative Reactions (Blood)

Answer 11

Ascorbic acid
High sp gr.
Formalin
Hypertension medication (Captopril)
High concentrations of nitrite
Failure to mix specimen

Question 12

Multistix (blood)

Answer 12

uses peroxide less subject to reduction by ascorbic acid

Question 13

Chemstrip (blood)

Answer 13

overlays the reagent pad with an iodate-impregnated mesh that oxidises ascorbic acid.

Question 14

Bilirubin

Answer 14

Highly pigmented yellow compound

Degradation product of hemoglobin

Question 15

Reagent strip reaction on bilirubin

Answer 15

Diazo reaction
2,4-dichloroaniline diazonium salt
2,6-dichlorobenzene-diazonium-tetrafluoroborate
Acidic medium
tan to violet

Question 16

Ictotest

Answer 16

Bilirubin
p-nitrobenzene-diazonium-p-toluenesulfonate
SSA
sodium carbonate
boric acid
blue to purple

Question 17

False Positive Reactions (Bilirubin)

Answer 17

Urine pigments
Phenazopyridine
indican
metabolites of Lodine

Question 18

False Negative Reactions (Blood)

Answer 18

Not fresh specimen
photo-oxidized bilirubin
hydrolysis of bilirubin diglucoronide
ascorbic acid
nitrite

Question 19

Urobilin

Answer 19

brown color of feces

Question 20

Multistix (urobilinogen)

Answer 20

Ehrlich’s aldehyde reaction
p-dimethylaminobenzaldehyde
light to dark pink

Question 21

Chemstrip (urobilinogen)

Answer 21

azo-coupling (diazo reaction)
4-methoxybenzene-diazonium-tetrafluroborate
white to pink

Question 22

False Positive Reactions (Urobilinogen)

Answer 22

Ehrlich-reactive compounds
pophobilinogen
indican
p-aminosalicylic acid
sulfonamides
methly dopa
procaine
chlorpromazine
heavy meal

Question 23

False Negative Reactions (Urobilinogen)

Answer 23

improperly preserved
nitrite
formalin

Question 24

Watson-Schwartz Differentiation Test

Answer 24

Urobilinogen is soluble in chloroform and butanol

Question 25

Hoesch test

Answer 25

``` rapid screening or monitoring of urinary porphobilinogen Hoesch reagent (Ehrlich reagent dissolved in 6 M HCL) ```

Question 26

Nitrite

Answer 26

UTI Bladder infection (cystitis) pyelonephritis

Question 27

Greiss reaction

Answer 27

Nitrite acidic pH p-arsanilic acid / sulphanilamide -> diazonium compound (tetrahydrobenzoquinolin) pink

Question 28

False Negative Reactions (Nitrite)

Answer 28

Large number of bacteria (further reduction of nitrite to nitrogen) Antibiotics ascorbic acid high sp gr

Question 29

LE test

Answer 29

detect presence of WBCs that have been lysed dilute alkaline urine Indicators of UTI Longest time of all reagent strip reactions

Question 30

False Negative Reactions (LE)

Answer 30

protein glucose oxalic acid ascorbic acid