Chemical Examination Flashcards
1
Q
Testing of a urine specimen should be done as soon as possible (within ___ hours) after collection.
A
2 hours
2
Q
Principle of pH
A
Double Indicator System
3
Q
Reading time of pH
A
Immediate (60 seconds)
4
Q
Indicator of pH
A
Methyl Red
Bromthymol Blue
5
Q
Correlation of pH: (3)
A
Nitrite
Leukocyte Esterase
Microscopic
6
Q
Clinical Significance of Urine pH (6)
A
- Respiratory or metabolic acidosis/ketosis
- Respiratory or metabolic alkalosis
- Defects in renal tubular secretion and reabsorption of acids and bases
- Treatment of UTIs
- Precipitation/ identification of crystals
- Determination of unsatisfactory specimens
7
Q
The most common chemical abnormalities detected in urine are increased amounts of: (7)
A
- sugars (e.g., glucose, galactose)
- protein
- RBCs
- WBCs
- bilirubin
- ketones
- urobilinogen
8
Q
a diet high in vegetables and fruits makes the urine pH more?
A
Alkaline
9
Q
Normal pH range
A
4.6 - 8
10
Q
High protein intake results in _________ urine
A
Alkaline
11
Q
Principle of Protein
A
Protein Error of Indicator
12
Q
Normal protein concentration excreted into the urine
A
10 mg/dL or 100 mg/24hours
13
Q
This protein makes up 1/3 of the total protein excreted into the urine
A
Albumin
14
Q
If 1/3 of proteins in urine is albumin, what are the remainder of these proteins?
A
Small globulins with molecular weight of < 50,000
15
Q
This buffer is incorporated in protein reagent strip
A
Citrate buffer
16
Q
pH and indicator of protein
A
pH - 3
Indicator - Tetrabromphenol blue
17
Q
Color of indicator at pH 3
A
Yellow
18
Q
Trace value of protein
A
30 mg/dL
19
Q
Three major categories of causes of Proteinuria:
A
Pre-renal
Renal
Post- renal
20
Q
Major category of causes of proteinuria:
- caused by conditions affecting the plasma prior to reaching the kidney
-not indicative of actual renal disease
A
Pre-renal protenuria
21
Q
Major category of causes of proteinuria:
- associated with true renal disease
- maybe the result of either glomerular or tubular damage
A
Renal Proteinuria
22
Q
caused by the addition of protein to the urine as it passes through the structure of the lower urinary tract
A
Post-renal protenuria
23
Q
Reaction interference in Protein
Cause of false positive protein: (6)
A
- highly buffered interference alkaline urine
- pigmented specimens,
- detergents
- antiseptics
- loss of buffer from prolonged exposure of the strip to the specimen reagent
- high specific gravity
24
Q
Correlations of Protein: (4)
A
- Blood
- Nitrite
- Leukocytes
- Microscopic
25
Reaction interference in Protein
Cause of false negative protein: (2)
1. Proteins other than albumin
2. Microalbuminuria
26
Principle of Glucose
Double Sequential Enzymatic Reaction (Glucose Oxidase)
27
Glucose is usually detected in urine. It is excreted into the urine when the plasma level reaches renal threshold of 160 - 180 mg/dL.
A. First statement is true, second statement is true.
B. First statement is correct, second statement is incorrect.
C. First statement is incorrect, second statement is correct.
D. First statement is false, second statement is false.
C. First statement is incorrect, second statement is correct.
Glucose is not usually detectable in urine.
28
Enumerate the disease associated with Hyperglycemia-associated glycosuria: (8)
1. Diabetes mellitus
2. Pancreatitis
3. Pancreatic cancer
4. Cushing syndrome
5. Hyperthyroidism
6. CNS damage
7. Stress
8. Gestational diabetes
29
Enumerate the disease associated with Renal-associated glycosuria: (8)
1. Fanconi syndrome
2. Advanced renal disease,
3. Pregnancy
4. Osteomalacia
30
Reaction interference in Glucose reagent strip that occurs due to contamination by oxidizing agents and detergents
False-positive
31
Reaction interference in Glucose reagent strip that occurs due to high levels of ascorbic acid, high levels of ketones, high specific gravity, low temperature, improperly preserved specimens
False negative
32
Correlation of Glucose: (2)
1. Ketones
2. Protein
33
This is the product of incomplete fat metabolism
Ketones
34
Presence of ketones in urine indicates what?
Acidosis
35
Three ketone bodies present in urine:
Acetoacetic (diacetic) acid
Acetone
3-hydroxybutyrate.
36
Principle of Ketones
Sodium Nitroprusside reaction
37
The test detects acetone and 3-hydroxybutyrate. If one ketone is excreted, all are excreted.
A. First statement is true, second statement is true.
B. First statement is correct, second statement is incorrect.
C. First statement is incorrect, second statement is correct.
D. First statement is false, second statement is false.
C. First statement is incorrect, second statement is correct.
The test does not detect acetone and 3-hydroxybutyrate.
38
Clinical significance of Ketones
1. Diabetic acidosis
2. Insulin
3. Dosage monitoring
4. Starvation
5. Malabsorption/pancreatic disorders
6. Strenuous exercise
7. Vomiting
8. Inborn errors of metabolism
39
Reaction interference of ketones that are caused by the following:
1. Phthalein dyes
2. Highly pigmented red urine
3. Levodopa
4. Meds containing free sulfhydryl groups
False positive
40
What causes false negative result in ketones?
Improperly preserved specimen
41
Correlation of Ketones: (1)
Glucose
42
Principle of Blood
Pseudoperoxidase (activity of Hemoglobin)
43
This type of bloody urine is caused by destruction of RBCs
Hemoglobinuria
44
This type of bloody urine is seen with intact RBCs
Hematuria
45
Major causes of Hematuria: (8)
1. Renal calculi,
2. Glomerulonephritis
3. Pyelonephritis
4. Tumors
5. Trauma
6. Exposure to toxic chemicals
7. Anticoagulants
8. Strenuous exercise
46
Hematuria is closely related to which disorder?
Disorders of Renal or genitourinary origin
47
Bleeding from the renal or genitourinary origin is the result of what?
Trauma or damage to organ system
48
Hemoglobinuria can be the result of: (3)
1. Lysis of RBCs produced in the urinary tract
2. Intravascular Hemolysis
3. Subsequent filtering of hemoglobin through the glomerulus
49
Hemoglobinuria occurs in cases of: (7)
1. Transfusion reactions
2. Hemolytic anemias
3. Severe burns
4. Infection/malaria
5. strenuous Exercise
6. RBC trauma
7. Brown recluse spider bites
50
Myoglobinuria is suspected in patients with conditions associated to what?
Associated with muscle destruction (rhabdomyolysis)
51
Conditions associated with muscle destruction: (9)
1. Trauma
2. Crush syndromes,
3. Prolonged coma
4. Convulsions
5. Muscle-wasting diseases
6. Alcoholism
7. Heroin abuse
8. Extensive exertion,
9. may also be a side effect of cholesterol-lowering statin medications
52
Reaction interference that causes false positive result in blood:
1. Strong oxidizing agents
2. Bacterial peroxidases
3. Menstrual contamination
53
Reaction interferences that causes false-negative result in blood:
1. high specific gravity/crenated cells (Hypersthenuric urine)
2. Formalin
3. Captopril
4. high concentrations of nitrite
5. Ascorbic acid
6. Failure to mix the specimen prior to testing
54
Correlation of Blood: (2)
1. Protein
2. Microscopic
55
This reagent strip parameter is not normally detected in urine; early indication of liver disease
Bilirubin
56
Principle of Bilirubin
Diazo reaction
57
Describe Diazo Reaction in Bilirubin
2,4 dichloroaniline diazonium salt reacts with bilirubin to produce a tan-to-purple color
58
Clinical significance of Bilirubin: (4)
1. Hepatitis
2. Cirrhosis
3. Other liver disorders
4. Biliary obstruction (gallstones, carcinoma)
59
Reaction interference in bilirubin that causes false-positive result:
1. Highly pigmented urine
2. Indican
3. Metabolites of Iodine
60
Reaction interference in bilirubin that causes false-negative result:
1. Specimen's exposure to light
2. Ascorbic acid
3. High concentration of Nitrite
61
Correlation of Bilirubin: (1)
Urobilinogen
62
This appears in the urine because, as it circulates in the blood back to the liver, it passes through the kidney and is filtered by the glomerulus.
Urobilinogen
63
Principle of Urobilinogen
Ehrlich's reaction (Paradimethylaminobenzaldehyde)
64
Clinical significance of Bilirubin: (6)
1. Early detection of liver disease
2. Liver disorders
3. Hepatitis
4. Cirrhosis
5. Carcinoma
6. Hemolytic disorders
65
Reaction interference of urobilinogen that is caused by highly pigmented urine:
False positive
66
Reaction interference of urobilinogen that results from old specimens, preservation in formalin, and high concentration of nitrite
False negative
67
Correlation of Urobilinogen: (1)
Bilirubin
68
This reagent strip parameter provides a rapid
screening test for the presence of Urinary tract infecion
Nitrite
69
Principle of Nitrite:
Greiss reaction
70
How does pink colored strip occurs in presence of Nitrite in urine?
In Greiss reaction, the nitrites detected react with an aromatic amine at an acid pH.
The resultant azo product reacts with a hydrobenzoquinolin compound to form a pink color in the presence of nitrite
71
Nitrite reagent strip result are reported only as:
Positive or Negative
72
Clinical significance of Nitrite: (5)
Valuable for detecting:
1. Cystitis
2. Pyelonephritis
3. Evaluation of Antibiotic therapy
4. Monitoring of patients at high risk for UTI
5. Screening of urine culture specimen
73
Reaction interference in Nitrite that causes false positive result: (7)
1. Nonreductase-containing bacteria
2. Insufficient contact time between bacteria and urinary nitrate
3. Lack of urinary nitrate
4. Large quantities of bacteria converting nitrite to nitrogen
5. Presence of antibiotics
6. High concentrations of ascorbic acid
7. High specific gravity
74
Reaction interference in Nitrite that causes false negative result: (2)
1. Improperly preserved urine
2. Highly pigmented urine
75
Correlations of Nitrite: (3)
1. Protein
2. Leukocytes
3. Microscopic
76
This offers a more standardized means for the detection of leukocytes, also detects the presence of lysed leukocytes in dilute alkaline urine.
Leukocyte Esterase
77
Principle of Leukocyte Esterase:
Hydrolysis of Ester
78
What color is produced when aromatic acid reacts with a diazonium salt in LE reagent strip pad?
Purple color
79
Clinical significance of LE: (3)
1. Indicates bacterial and nonbacterial UTI
2. Inflammation of the urinary tract
3. Screening of urine culture specimens
80
False positive LE result is caused by:
1. Strong oxidizing agents
2. Formalin
81
False negative LE result is caused by: (8)
High concentrations of:
1. Protein
2. Glucose
3. Oxalic acid
4. Ascorbic acid,
5. Gentamicin
6. Cephalosporins
7. Tetracyclines
8. Inaccurate timing
82
Correlation of LE: (3)
1. Protein
2. Nitrite
3. Microscopic
83
Principle of Specific Gravity:
Changes in dissociation constant (pKa) of a polyelectrolyte
84
The higher the concentration of urine, the more hydrogen ions are released. This increases the pH.
A. First statement is true, second statement is true.
B. First statement is correct, second statement is incorrect.
C. First statement is incorrect, second statement is correct.
D. First statement is false, second statement is false.
B. First statement is correct, second statement is incorrect.
Increasing hydrogen ions decreases urine pH.
85
Reagent pad's specific gravity when it has blue color
1.000 (alkaline)
86
Reagent pad's specific gravity when it has green to yellow color
1.030 (Acid)
87
Clinical significance of SG: (4)
1. Valuable in monitoring patient hydration and dehydration
2. Loss of renal tubular concentrating ability
3. diabetes insipidus
4. determination of unsatisfactory specimens due to low concentration
88
Principle of Ascorbic acid:
Action of ascorbic acid to reduce a dye
89
Bonus: Importance of Ascorbic Acid detection
Ascorbic acid at higher concentration in urine samples can lead to false negative results in a number of urine tests, with a potential risk of clinical findings being overlooked, particularly with glucose and hemoglobin.
(pubmed)
89
Bonus: Importance of Ascorbic Acid detection
Ascorbic acid at higher concentration in urine samples can lead to false negative results in a number of urine tests, with a potential risk of clinical findings being overlooked, particularly with glucose and hemoglobin.
(pubmed)
