3- Chemical Analysis of Urine Flashcards
(89 cards)
1
Q
Def: a basic diagnostic tool used to determine pathological changes in a patient’s urine in standard urinalysis
A
urine test strip
2
Q
urine test strip aka
A
dipstick
3
Q
whats the time frame to read the dipstick
A
60 to 120 seconds
4
Q
Urine pH normally fluctuates between
A
acidic and alkaline
5
Q
what is the Acid indicator
A
methyl red
6
Q
what is the Alkaline indicator
A
bromthymol blue
7
Q
Urine pH range
A
5.0 to 8.5
8
Q
more phosphates, sulfates results in more
A
acidic urine
9
Q
Vegetable diet results in urine pH higher than
A
6
10
Q
Factors resulting in persistent Acidity
A
– Dehydration
– Diarrhea
– Fever
– Diabetes ketoacidosis
– Gout
– Pulmonary emphysema
– High protein diets or cranberries
– Renal tubular acidosis (proximal tubular, distal tubular) metabolic acidosis
– Acidifying drugs ( for ammonium magnesium stone prevention)
11
Q
Factors resulting in persistent Alkalinity
A
– Acute and chronic renal failure
– Urinary tract infections
– Bacterial contamination of urine
– Alkaline drugs
– Diuretics
12
Q
the source of low–molecular weight protein could be found in the urine
A
genito-urinary tract
13
Q
Mucoprotein Tamm-Horsfall (T-H) is secreted by
A
renal tubules (renal epithepial cells)
14
Q
Mucoprotein Tamm-Horsfall (T-H) is not derived from
A
blood plasma
15
Q
the amount of T-H protein is
excreted in urine?
A
Less than 150 mg/24 h (or 20 mg/dL)
16
Q
T-H protein is a ____ for formation of calculi or casts
A
matrix
17
Q
Testing for protein is based on
A
Protein Error of pH Indicators
18
Q
define “Protein Error of pH Indicators”
A
ability of protein to alter the color of some acid-base indicators without altering the pH
19
Q
Protein Error of pH Indicators is more sensitive
to _____ than ______
A
more sensitive to albumin than to globulin
20
Q
Urine protein:
false positive May result from
A
- highly buffered alkaline urine (medications or old urine)
- prolonged exposure to the sample (too long)
- container cleaning compounds (quaternary ammonia)
- some skin cleaners
- blood in urine
21
Q
Urine protein:
false negative may result from:
A
- diluted urines
- elevated amounts of proteins other than albumin
22
Q
Urine protein: significance
Which factors which could result in temporary proteinuria (transient proteinuria, “trace”):
A
- strenuous exercise
- postural proteinuria
- dehydration
- exposure to heat or cold
- fever
- emotional stress
- pregnancy
23
Q
what Diseases tha resutl in persistent proteinuria
A
- glomerulonephritis
- pyelonephritis
- malignant hypertension
24
Q
____ % of glucose is reabsorbed in the proximal tubules
A
100%
25
**\*\*\*** **Usually, urine doesn't present unless threshold levels exceeded \_\_\_\_\_\_**
**160-180 mg/dl**
26
**\*\*\* Dipstick test is sensitive for what kind of sugars?**
**Glucose only**
27
Urine glucose:
false positive may result from
- after using oxidizing cleaniers (peroxide, hypochlorite)
- in patients taking Levodopa (Parkinson's disease)
- high levels of **ketones** in urine
28
Urine glucose:
false negative may result from
- cool urine
- high specific gravity urine (due to uricosuria)
- alkaline urine due to bacterial contamination of old urine
- ascorbic acid (Vitamin C) in high doses can inhibit the enzymatic reaction
29
Glucose can be present in urine after how many hours from eating sweets?
2 hours
30
urine glucose that presnt after eating sweets is known as:
transient glucosuria
31
Glucosuria depends on
– blood glucose levels
– glomerular filtration rate
– tubular reabsorption
32
**Glucosuria is seen in patient with**
(what conditions)
**diabetes mellitus**
**congenital forms of glucosuria**
33
Persistent glucosuria develops in:
- diabetes mellitus
- CNS problems (stroke, neoplasms)
- kidney problems (e.g. uremia)
- endocrine problems (e.g. acromegaly, pheochromocytoma)
- liver disorders (e.g. glycogen storage disease)
- pharmaceutical agents (e.g. diuretics, birth control pills)
34
a second method for the measurement of sugar in urine
Clinitest
35
what kind of sugars does clinitest measures?
**Glucose**, and other reducing sugars
36
Clinitest: false positive may result from
• Ascorbic acid
• Cephalosporins
• Probenecid (treating gout and hyperuricemia)
• Urinary preservatives:
– formalin
– formaldehyde
– formaldehyde
37
Clinitest: false negative may result from
Technique **errors**
38
what test is used to determine the presence of
reducing sugars?
Benedict’s test
39
reducing sugars in urine includes
fructose
glucose
maltose
galactose
lactose
40
Urine reducing sugar test Is used for early screening detection of
**galactosemia or diabetes**
41
\_\_\_\_\_ are produced normally by the **liver** as part of
fatty acid metabolism
**Ketones**
42
Normally, the urine **(should/should not)** contain a noticeable concentration of ketones
**Should not**
43
Dipstick test determines wich acid? **(acetoacetic acid/beta-hydroxybutyric acid)**
**acetoacetic acid**
44
Urine ketones: false positive or atypical color
results from:
• Highly pigmented urine
• Combination of **high specific gravity and a low pH**
• Dehydration
• Phenylketones
• Some medications
• Ascorbic acid
• Positive and questionable results may be confirmed with a
tablet test
45
Urine ketones: false negative
resutls from
* Delay in testing (old urine)
* Loss of reagent reactivity
46
Urine ketones confirmatory test is called
**Acetest**
47
does Acetest react with beta-hydroxybutyric acid?
No
(no body likes beta-hydroxybutyric)
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48
• Ketone bodies can be determined in the following diseases:
- diabetes mellitus
- malabsorption syndrome (diarrhea)
- exposure to cold
- fasting
- fever
- insufficient carbohydrate intake
- malnutrition
- strenuous exercise
- vomiting
49
**Hematuria**: blood in urine may be released from any organ of \_\_\_\_\_\_\_\_
**genito-urinary** tract
50
Hemoglobinuria is due to
intravascular distraction of RBC - Glomerular filtrate
51
Myoglobinuria is due to
muscle damage - Glomerular filtrate
52
Blood color chart
53
Urine blood/hemoglobin: false positive
* Cleanser - Oxidizing contaminant (Hypochlorites)
* Bacterial peroxidases
* Menstrual blood
54
Urine blood/hemoglobin: false negative
* Technique errors inadequate mixing of urine sample
* Formalin preservative
* High concentrations of ascorbic acid (Vitamin C)
* High specific gravity
* Nitrites
* Proteins
55
Define **Hematuria**
the presence of **blood** or **intact RBCs** in the urine
56
highly alkaline urine or has a very lowspecific gravity (1.007) can cause the red cells to
Lyse and release hemoglobin to urine
57
empty red cell membranes aka
“ghost” cells
58
**Transient** hematuria may result from:
- strenuous exercises
- menstrual contamination
59
* *Persistent** hematuria:
- can develop in renal diseases in:
glomerular
tubular
interstitial
vascular
trauma of kidneys
60
* *Persistent** hematuria:
- also present in patients with
urolithiasis (kidney stones)
urinary tract infections
urinary tract tumors
```
bleeding disorders related to anticoagulant therapy prostatic cancer
gynecological disorders
virus infection (e.g. Ebola)
```
61
Define myoglobinuria
Damage to cardiac or skeletal muscles
62
Both hemoglobin & myoglobin will be + on strip blood results becasue both contain:
heme
63
Normal Bilirubin Pathway
64
because only conjugated bilirubin appears in
urine, **bilirubinuria** implies what diseases?
**Liver or cholestatic diseases**
65
Why unconjugated bilirubin is **not** filtered by the glomerulus?
bilirubin is tightly bound to albumin
66
A positive test for urine bilirubin confirms that any raised plasma levels are from:
**conjugated hyperbilirubinemia**
67
Normally, _____ amounts of bilirubin are present in urine
no detectable
68
Urine bilirubin: false positive
• Technique errors:
– reading after the prescribed time
• Atypical color reactions produced by some medicines
• Confirm results with Ictotest
69
Urine bilirubin: false negative
• Large amounts of ascorbic acid decrease the sensitivity of the dipstick
• High levels of nitrite
• Exposure to light and room temperature
– bilrubin oxidizes to biliverdin
70
Urine bilirubin confirmatory test is called
Ictotest
71
The presence of bilirubin in urine indicate to:
– gallbladder, bile duct obstruction
– liver pathology (e.g. hepatitis)
72
About **\_\_\_\_%** of urobilinogen reabsorbed into the bloodstream, returns to the liver, and reexcreted into the intestines
**10–15**
73
Normal level of urobilinogen excretion
**1–4 mg/24 h**
or
**less than 1.0 Ehrlich unit/2h**
74
Urobilinogen color chart
75
Urine urobilinogen: false positive
* aspirin
* sulfonamides
* nitrites (e.g. in UTI)
* porphyria
76
– which test is used to differentiate
between **porphobilinogen and urobilinogen**
**Watson-Schwartz** test
77
Urine urobilinogen: false negative
* Use of stale urine that has been exposed to light
* Formalin
* Antibiotics (broadspectrum) which alter the normal
bacteria flora in the intestines, because urobilinogen
cannot be formed in the intestines.
bacteria flora in the intestines, because urobilinogen
cannot be formed in the intestines.
78
urobilinogen Peak levels between
2-4 p.m
79
urobilinogen Elevated in
(diseases)
– Liver disease
– Intestinal obstruction
– Hemolytic anemia
80
a **rapid**, indirect method for the **early
detection**of significant and asymptomatic**bacteriuria**
**nitrite**
81
To convert nitrate to nitrite, urine must have incubated in the bladder for a **minimum of**
**4 hours**
82
If UTI is caused by \_\_\_\_\_\_\_\_\_\_, the reaction will be negative
**non-nitrate** reducers (e.g. Mycobacteria),
83
Nitrite color chart
84
Urine nitrite: false **positive**
The dipstick is **highly sensitive to air** exposure
The urine should be tested shortly after voided, because at room temperature for several hours specimen could be contaminated by bacteria
85
Urine nitrite: false negative
* Specimen containing non-nitrate reducing pathogens
* Insufficient time in the bladder (less than 4 hours)
* Low or no nitrate diet
* Elevated specific gravity of urine
* High level of urobilinogen in urine
* Ascorbic acid
86
If there are clinical symptoms, then ______________ should be performed, even if the nitrite test is negative
regular bacteriology tests
87
Leukocyte Esterase color chart
88
Urine leukocyte esterase: false positive
* Trichomonas infection
* Contamination by vaginal discharge
* Formalin used as preservative
89
Urine leukocyte esterase: false negative
* High level of Ascorbic acid
* High level of protein, glucose ( high specific gravity)
* Some antibiotics (Cephalexin, Keflex,Tetracycline)
