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Liz's Urinalysis > Introduction to Urinalysis > Flashcards

Introduction to Urinalysis Flashcards

1
Q

Primary functions of the urinary system

A
  • Regulating plasma concentrations of Na+, K+, Cl-, Ca2+, and other ions
  • Regulating blood volume and blood pressure
  • Contributing to the stabilization of the blood pH
  • Conserving valuable nutrients
  • Eliminating organic wastes
  • Synthesizing calcitriol
  • Assisting the liver in detoxifying the blood and deaminating amino acids
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2
Q

Which parts of the nephron are located w/in the cortex?

A
  • Glomeruli (where filtration occurs)
  • PCT
  • DCT
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3
Q

Which parts of the nephron are located w/in the medulla?

A

Renal pyramid (loops of Henle inside this) and sinus (w/ minor calyces that merge to form the major calyx)

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4
Q

The medulla is ____ to the lumen

A

Hyperosmotic

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5
Q

Function of the glomerulus

A

Responsible for the production of the filtrate; located at the proximal end of the proximal tubule

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6
Q

Function of the proximal convoluted tubule

A
  • Significantly reduces the volume of water in the filtrate by reabsorbing approximately 2/3
  • Na+, Cl-, glucose, and amino acids are absorbed from filtrate
  • Removes unfiltered proteins or drugs out of the blood
  • Secretes H+
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7
Q

Function of the descending limb of the Loop of Henle

A
  • Passively removes water out of the lumen
  • Permeable to urea
  • Impermeable to Na+ and Cl-
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8
Q

Function of the ascending limb of Loop of Henle

A
  • Na+ and Cl- are actively moved out of the lumen
  • Impermeable to water
  • Permeable to urea
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9
Q

Function of the distal convoluted tubule

A

In the presence of aldosterone, Na+ is actively transported out of the lumen (followed by water)

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10
Q

Function of the collecting duct

A

Determines the final concentration of urine

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11
Q

JGA senses decreases in __________ ______ and releases renin which stimulates the production of angiotensin II which in turn stimulates the adrenal cortex to secrete aldosterone

A

Na+; blood volume

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12
Q

Aldosterone actively increases _____ ______ from the lumen of the distal convoluted tubule and collecting duct and thus ______ pulls water out of the lumen. _______ is secreted into the lumen.

A

Na+ absorption; passively; K+

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13
Q

_______ in the heart sense a drop in blood pressure, increase in plasma osmolality, and/or exposure to aldosterone

A

Baroreceptors

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14
Q

The ______ synthesizes ADH which is transported to the pituitary gland for storage before it is released into the bloodstream

A

Hypothalamus

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15
Q

ADH causes changes in the epithelium of the _____ ______ _____ and _____ ______ that enhance the passive flow of water out of the lumen

A

DCT and CD

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16
Q

Patient with decreased blood pressure will compensate by doing what?

A

Produce more aldosterone

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17
Q

Three primary pigments found in the urine

A
  • Urochrome
  • Urobilin
  • Uroerythrin
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18
Q

This substance indirectly stimulates the production of aldosterone

A

Renin

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19
Q

This is the primary source of yellow coloration and is produced at a constant rate; primarily responsible for urine coloration

A

Urochrome

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20
Q

This is an orange-brown colored pigment formed by the oxidation of urobilinogen; commonly found in old urines

A

Urobilin

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21
Q

This is a pink pigment that attaches to urates in the urine and gives amorphous urates a pinkish hue

A

Uroerythrin

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22
Q

Yellow foam in urine is most commonly due to what?

A

Bilirubin

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23
Q

White foam in urine is most commonly due to what?

A

Protein

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24
Q

This is a drug used to reduce discomfort in UTIs, causing urine to be very orange and obscures chemical testing

A

Pyridium

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25
Q

What three things are reported on urine containing pyridium?

A
  • Color
  • Clarity
  • Specific gravity (by refractometer)
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26
Q

What is the clarity of normal urine?

A

Clear

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27
Q

List some nonpathologic states of slight turbidity in clear urine

A
  • Amorphous phosphates precipitate out in alkaline urine
  • Amorphous urates, calcium oxalates, or uric acid precipitate out in acidic urine
  • Carbonates
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28
Q

List some nonpathogenic states of cloudy specimens

A
  • Squamous epis from improper collection
  • Bacteria (improper storage allows them to grow)
  • Sperm
  • Talcum powder
  • Vaginal creams
  • Radiogrpahic contrast
  • Fat or chyle (digested from lymph vessels)
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29
Q

List some pathologic states from cloudy urine

A
  • Bacteria
  • Yeast
  • Fungi
  • RBCs
  • WSBCs
  • Trichomonas
  • Fecal contamination
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30
Q

Describe a clear urine

A
  • No haziness
  • Easy to read printed material
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31
Q

Describe a slightly cloudy urine

A

Printed material is readable

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32
Q

Describe a cloudy urine

A

Printed urine material may still be seen but it won’t be readable

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33
Q

A ratio between the density of urine and the density of distilled water at the same temperature; a measure of the kidney’s ability to maintain the body’s water and chemical balance through reabsorption

A

Specific gravity

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34
Q

Specific gravity measures the amount of ____ ____; depends on the ____ and ____ of dissolved particles

A

Dissolved solids; mass; number

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35
Q

What is the principle of the refractometer?

A

Refractive index → ratio of the velocity of light through air is compared to the velocity of light through a solution

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36
Q

How do you correct the specific gravity in a refractometer for glucose?

A

For every gram of glucose/dL, subtract 0.004

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37
Q

How do you correct the specific gravity in a refractometer for protein?

A

For every gram of protein/dL, subtract 0.003

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38
Q

How can the [glucose] and [protein] be determined?

A

By the reagent strip

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39
Q

Why does using centrifuged or uncentrifuged urine not affect the specific gravity when using a refractometer?

A

B/c we’re measuring dissolved substances

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40
Q

In measuring specific gravity by reagent strip, when urine pH is ≥7.0, add ____ to the strip reading if it’s being read manually

A

0.005

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41
Q

Is there interference from glucose, protein, or radiographic dyes when measuring specific gravity by reagent strip?

A

NO

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42
Q

What is the specific gravity of the filtrate as it leaves the glomerulus?

A

1.010

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43
Q

Three factors that affect the refractive index of a solution

A
  • Wavelength
  • Temperature
  • Concentration
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44
Q

This term is used to describe urine w/ a specific gravity of 1.010

A

Isosthenuria

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45
Q

This term is used to describe urine w/ a specific gravity of < 1.010

A

Hyposthenuric

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46
Q

If urine is constantly < 1.010 (hyposthenuric) what does this represent?

A

The kidney’s inability to concentrate urine

  • Diabetes insipidus
  • Renal disease
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47
Q

This term is used to describe ruine w/ a specific gravity of > 1.010

A

Hpersthenuric

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48
Q

If urine is constantly > 1.010 (hypersthenuric) what does this represent?

A
  • Adrenal insufficiency
  • CHF
  • Hepatic disease
  • Dehydration
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49
Q

What is the physiological limit of specific gravity?

A

1.040

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50
Q

If urine has a specific gravity < 1.003, what does this represent?

A

Probably diluted w/ water

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51
Q

What factors influence hypersthenuric specimens?

A
  • Renal function
  • State of hydration
  • Volume of urine excreted
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52
Q

Low fluid intake = ____ specific gravity

A

High

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53
Q

High fluid intake = ____ specific gravity

A

Low

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54
Q

What factors could cause a specific gravity to be > 1.035?

A
  • Dehydration
  • Diabetes mellitus
  • CHF
  • Radiographic contrast
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55
Q

If the specific gravity is > 1.035, what should you do?

A

Make a 1:2 dilution w/ distilled water and multiply all digits to the right of hte decimal by your dilution factor

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56
Q

This is the measure of the concentration of dissolved particles in a solution expressed in osmoles of solute particles/kg of solvent

A

Osmolality

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57
Q

Osmolality only measures dissolved particles, thus _____ and ______ are not measured

A

Lipids and protein

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58
Q

Reference ranges for

  • Specific gravity
  • Urine color
  • Urine volume
A
  • Specific gravity: 1.003-1.030
  • Color: colorless to yellow
  • Volume: 600-2000 mL/day
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59
Q

Measurement of ____ is the most accurate method to determine solute concentration

A

Osmolality

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60
Q

Urine:serum osmolality ratio (U/S)

61
Q

Factors that influence daily urine volume

A
  • Fluid intake
  • Fluid loss from non-renal sources (vomiting, dirrhea, sweating)
  • Solute diuresis
  • Variation in ADH secretion
62
Q

This term is used when describing urine output < 400mL/24 hours; decreased volume is due to excess water loss

63
Q

This is known as the cessation of urine flow

64
Q

This term is used when describing an increased volume at night; caused by renal failure

65
Q

This term is used when describing an increased daily urine volume; caused by diabetes mellitus/insipidus, medications, diuretic therapy, caffeine, and alcohol

66
Q

List the proper criteria for a good specimen

A
  1. Proper patient ID (name, location, physician, collection date, collection time, test requested)
  2. Fresh collection (should be tested w/in 2 hours of collection)
  3. If testing is delayed, urine should be refrigerated
67
Q

What are the different types of collection techniques?

A
  • Routine
  • Clean Catch Midstream (CCMS)
  • Catheterization
  • Suprapubic aspiration
68
Q

Routine collection

  • Advantages
A
  • Ease
  • Good for screening (usually adequate for indicating a disease process)
69
Q

Routine collection

  • Disadvantages
A

Not ideal for reflex urine cultures

70
Q

This technique requires no preparation

71
Q

This technique is often used w/ random specimens

A

Clean catch midstream (CCMS)

72
Q

CCMS collection

  • Advantages
A
  • W/ education, easy to collect
  • Good specimen for urine culture and routine analysis
73
Q

CCMS collection

  • Disadvantages
A
  • Noncompliance in collection technique
  • Difficult for some patients
74
Q

Catheterization collection

  • Advantages
A
  • Specimens good for urine cultures and routine analysis
  • Urethral catheters enter the bladder
  • Ureteral catheters enter either of the ureters and can provide information about each kidney independently
75
Q

Catheterization collection

  • Disadvantages
A
  • Increases risk of UTIs
  • Medical staff needed
  • Discomfort for patients
76
Q

This technique involves collecting urine directly from the bladder by puncturing hte abdominal wall w/ a needle and syringe; usually performed for bacterial cultures (esp. for anaerobic specimens)

A

Suprapubic aspiration

77
Q

Suprapubic collection

  • Advantages
78
Q

Suprapubic collection

  • Disadvantages
79
Q

A sterile bag w/ an adhesive border is placed on the patient to collect the urine

80
Q

Pediatric collection

  • Advantages
A
  • Least invasive technique to attain specimen from an infant
  • Specimen is satisfactory for screening purposes
81
Q

Pediatric collection

  • Disadvantages
A
  • Inappropriate for urineculture due to many opportunities for contamination
  • Cumbersome
82
Q

List the types of specimens

A
  • Random
  • First morning
  • Fasting
  • TImed
  • Chain of custody
83
Q

Random urine

  • Advantages
A
  • No preparation
  • Anytime (usually daytime)
  • Usually satisfactory for routine screening and many disease processes will still be found
84
Q

Random urine

  • Disadvantages
A

Variances in fluid intake and exercise can affect urine composition

85
Q

First morning urine

  • Advantages
A
  • Ideal for testing specimens that require concentration and incubation such as nitrates, protein, and bacteria
  • Confirmation of orthostatic proteinuria
  • Formed elements (casts) more stable
  • Cells have better morphology
  • More epis for cytology studies
86
Q

First morning urine

  • Disadvantages
A
  • Additional crystals may precipitate upon cooling
  • More prep and the specimen must be preserved if not tested w/in 2 hours
87
Q

In this type of collection, the goal is to eliminate metabolites from food ingested prior to the beginning of the fasting period; often used for glucose monitoring for patients w/ diabetes mellitus or gestational diabetes

A

Fasting urine

88
Q

This type of urine requires the patient to void immediately before eating and the collect urine 2 hours post eating; used for diabetes mellitus monitoring

A

2 hour postprandial

89
Q

Any urine that is collected during a specific time frame w/in a 24 hour period

A

Fractional urine

90
Q

this type of urine collection is used because of circadian and diurnal variations in hormones, proteins, glomerular filtration rates, exercise, hydration, etc; usually 12 or 24 hour collection; preservative is usually in the bottle before patient takes it home

A

Timed urine

91
Q

Timed urine

  • Disadvantage
A
  • Preservatives and/or refrigeration may be required
  • Many errors due to handling problems, storage problems, loss of a specimen, two morning specimens, etc
92
Q

When measuring a urine’s specific gravity using a reagent dipstick, are you required to correct for elevated urine glucose?

A

NO! The reagent strip is not affected by elevated glucose levels

93
Q

Color will ____ w/ time

94
Q

Clarity ____ due to bacterial growth and ____ of ____ materials

A

Decrease; precipitation; amorphous

95
Q

pH ____ due to decomposition of urea to NH3 and loss of CO2 as a specimen is allowed to sit out, unpreserved

96
Q

Glucose ____ due to bacterial consumption as a urine is allowed to sit out, unpreserved

97
Q

Ketones ____ due to bacterial action and will vaporize as a urine is allowed to sit out, unpreserved

98
Q

Bilirubin ____ due to photo-oxidation as a urine is allowed to sit out, unpreserved

99
Q

Urobilinogen ____ due to oxidation to urobilin as a urine is allowed to sit out, unpreserved

100
Q

Nitrites are ____ due to bacterial production as a urine is allowed to sit out, unpreserved

101
Q

Nitrites are ____ due to conversion of nitrite to nitrogen gas as a urine is allowed to sit out, unpreserved

102
Q

RBCs, WBCs, and casts ____ as a urine is allowed to sit out, unpreserved

103
Q

Bacteria ____ as a urine is allowed to sit out, unpreserved

104
Q

What is the most common method of preservation?

A
  • Refrigeration at 4-6°C

**REMEMBER: allow urine to reach room temp before testing!

105
Q

Advantages of refrigerating urine specimens

A
  • Easy
  • Prevents bacterial proliferation (culture is still possible up to 24 hours)
  • Does not interfere w/ most analytes
106
Q

Disadvantages of refrigerating urine specimens

A
  • Precipitation of amorphous urates, and phosphate crystals that interfere w/ microscopic analysis
107
Q

Culture of a refrigerated specimen is preferred in ___ hours but will be accepted up to ___ hours

A

8 hours; 24 hours

108
Q

Culture on an UNREFRIGERATED specimen must be performed within ___ hours post collection

109
Q

Commonly used preservative for 24 hours urine collections

A

Boric acid

110
Q

Advantages of using boric acid as a preservative

A
  • Preserves proteins and formed elements
  • Bacteriostatic so specimen can be used for collection
111
Q

Disadvantages of using boric acid as a preservative

A
  • Precipitates out many crystals
  • ↓ pH - Interferes w/ drug and hormone analysis
112
Q

Advantages of using formalin as a preservative

A

Excellent cell preservative

113
Q

Disadvantages of using formalin as a preservative

A

Interferes w/ glucose, blood, leukocyte esterase, and copper reduction testing (clinitest)

114
Q

Advantages of mucolexx as a preservative

A

Preserves sediments such as cells and casts

115
Q

Advantages of toluene as a preservative

A
  • Does not interfere w/ most chemistry tests
  • Prevents contamination by airborne bacteria
116
Q

Disadvantages of toluene as a preservative

A
  • Does not prevent the proliferation of bacteria already in the specimen
  • Floats on the surface of the specimen and clings to pipettes, testing strips, etc.
117
Q

What should you do if a urine culture is ordered, or is expected to be ordered?

A

Pour off the specimen for the urine culture before dipping or pipetting

118
Q

Fresh and intact RBCs (hematuria) cause urine color to be what?

A

Pink → red

119
Q

How does hemoglobin and myoglobin appear in the urine?

A

Urine is clear, reagent strip is positive for blood

120
Q

____ in the urine is often accompanied by a reddish plasma

A

Hemoglobin

121
Q

____ in the urine is often accompanied by a clear plasma b/c it’s cleared from the blood quicker

122
Q

An accumulation of uroporphyrin causing port wine colored urine, color may be red but the strip may read negative

A

Porphyria cutanea tarda

123
Q

Accumulation of coproporphrinogen, red or colorless urine w/ fluorescence

A

Lead poisoning

124
Q

Brown, dark brown, or black urine can be caused by what three things?

A
  • Melanuria (melanin in the urine)
  • Alkaptonuria (homogenistic acid)
  • Medications
125
Q

Blue and green urine is caused by what three things?

A
  • Biliverdin (an oxidized form of bilirubin)
  • Bacterial infections (Pseudomonas)
  • Medications
126
Q

Pale yellow or colorless urine

  • Nonpathologic states
127
Q

Pale yellow or colorless urine

  • Pathologic states
128
Q

Dark yellow/amber/orange urine

  • Nonpathologic states
129
Q

Dark yellow/amber/orange urine

  • Pathologic states
130
Q

Red urine

  • Nonpathologic states
A
  • Menstrual contamination
  • Pigmented foods (beets, blackberries)
  • Medications
131
Q

Red urine

  • Pathologic states
132
Q

Brown/dark brown/black urine

  • Nonpathologic states
133
Q

Brown/dark brown/black urine

  • Pathologic states
134
Q

Blue and green urine

  • Nonpathologic states
135
Q

Blue and green urine

  • Pathologic states
136
Q

List some causes of red urine

A
  • Kidney stones
  • Lower urinary bleeds
  • Muscle injury
  • Rhabdomyolysis
  • Porphyria cutanea tarda
  • Lead poisoning
137
Q

What are the three main parts when examining urine?

A
  • Physical characteristics
  • Chemical characteristics
  • Microscopic elements
138
Q

Reference range for urine osmolality

A

275-900 mOsm/kg

139
Q

What is A?

140
Q

What is M?

141
Q

What is L?

A

Renal pyramid

142
Q

What is J?

A

Minor calyx

143
Q

What is I?

A

Major calyx

144
Q

What is H?

A

Renal lobe

145
Q

What is E?

A

Renal papilla

146
Q

What is D?

147
Q

What is B?

A

Renal pelvis

148
Q

Urine is an ultrafiltrate of what?

149
Q

The process solely responsible for water reabsorption throughout the entire nephron is ____ ____

A

Passive transport

Liz's Urinalysis (6 decks)

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