Chemical Analysis of Urine Flashcards

1
Q

pH of urine is reflection of:

A

ability of kidneys to maintain normal hydrogen ion concentration in plasma and extracellular fluid

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2
Q

urine pH has 2 main objectives

A

diagnostic

therapeutic

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3
Q

pH range of urine

A

5.0-8.5

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4
Q

vegetable diet results in urine pH of

A

higher than 6

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5
Q

diet high in protein results in urine pH that is more

A

acidic

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6
Q

factors resulting in persistent acidic diet

A
dehydration
diarrhea
fever
diabetes ketoacidosis
gout
pulmonary emphysema
high protein diet or cranberries
renal tubular acidosis
acidifying drugs
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7
Q

factors resulting in persistent alkalinity

A
acute and chronic renal failure
UTI
bacterial continuation of urine sample
alkaline drugs
diuretics
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8
Q

small amounts of low-molecular weight protein could be found in urine – from _______ tract

A

genito-urinary tract

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9
Q

mucoprotein Tamm-Horsfall (T-H) is secreted by _______ and is NOT derived from ______

A

renal tubules

blood plasma

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10
Q

less than ______ mg/24 hour of T-H protein is excreted and is the matrix for ______

A

150 mg/24 hour period

formation of calculi or casts

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11
Q

testing for protein in urine is based off of principle called _________, which is the ability of protein to alter the color of some acid-base indicators without altering pH

A

Protein Error of pH indicators

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12
Q

in a solution void of protein, pH =

A

3 (yellow)

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13
Q

in the presence of protein, color on dipstick changes to ____, then ____ based on concentration; this method is more sensitive to ______ than _____

A

green then blue

albumin than globulin

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14
Q

false positive of protein in urine may come from:

A
highly buffered alkaline urine
prolonged exposure to sample
container cleaning compounds
some skin cleaners
blood in urine
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15
Q

false negative of protein in urine may come from:

A

diluted urines

elevated amounts of protein other than albumin

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16
Q

factors that could contribute to temporary proteinuria

A
strenuous exercise
postural proteinuria
dehydration
exposure to heat or cold
fever
emotional stress
pregnancy
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17
Q

(3) diseases causing consistent proteinuria

A

glomerulonephritis
pyelonephritis
malignant HTN

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18
Q

100% of glucose is reabsorbed in _______; usually not present in urine unless _______ mg/dl in blood

A

proximal tubules

160-180 mg/dl

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19
Q

urine glucose false positive may come from: (3)

A

oxidizing cleaning agents for urine containers (hydrogen peroxide)
patients taking Levodopa (parkinson’s disease)
high levels of ketones in urine

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20
Q

urine glucose false negative may come from (4)

A

cool urine
urine with high specific gravity due to uricosuria
alkaline urine due to bacterial contamination of old urine
ascorbic acid (vit C) in high doses can inhibit enzymatic reaction

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21
Q

when glucose concentration is present in urine 2 hours after eating sweet foods

A

transient glucosuria

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22
Q

glucosuria depends on:

A

blood glucose levels
glomerular filtration rates
tubular reabsorption

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23
Q

glucosuria is seen in (2) diseases

A

diabetes mellitus

congenital forms of glucosuria

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24
Q

PERSISTENT glucosuria develops in: (6)

A
diabetes mellitus
CNS problem
kidney problems
endocrine problems
liver disorders
pharmaceutical agents
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25
Q

second method for measurement of glucose in urine; detects ALL _____ sugars except _____

A

Clinitest aka Benedict’s Test

reducing sugars except glucose

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26
Q

Clinitest (benedict’s test) is predominately used for diagnosing ______

A

galactosemia

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27
Q

false positives for Clinitest (4)

A

ascorbic acid
cephalosphorins
probenecid (treating gout and hyperuricemia)
urinary preservatives (formalin and formaldehyde)

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28
Q

false negatives for Clinitest (1)

A

technique errors

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29
Q

urine reducing sugar test is screening for GENETIC disorders of _______ metabolism; routinely performed in ______; early detection of ______

A

carbohydrate
newborns
galactosemia

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30
Q

ketones are normally produced by ______, as part of fatty acid metabolism

A

liver

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31
Q

if body cannot get enough _____ for energy, it will switch to using it’s body fats –> increase _____ production making them detectable in urine and blood

A

glucose

ketone

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32
Q

ketone bodies that commonly appear in urine when fats burned for energy (3)

A

acetoacetic acid
beta-hydroxybutyric acid
acetone

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33
Q

dipsticks test determine ______ for protein, but never ____ for protein

A
acetoacetic acid (sometimes acetone)
never beta-hydroxybutyric acid
34
Q

false positive for urine ketone with atypical color (6)

A
highly pigmented urine
combination of high specific gravity and low pH
dehydration
phenylketones
some meds
ascorbic acid
35
Q

(2) reasons for false negatives for urine ketons

A

delay in testing

loss of reagent activity

36
Q

ketone bodies can signify: (9)

A
diabetes mellitus
malabsorption syndrome
exposure to cold
fasting
fever
insufficient carb intake
malnutrition
strenuous exercise
vomiting
37
Q

positive dipstick for blood in urine

A

hematuria
hemoglobinuria
myoglobinuria

38
Q

blood in urine may be released from any organ of GENITO-URINARY tract

A

hematuria

39
Q

blood in urine due to intravascular distraction of RBC - Glomerular filtrate

A

hemoglobinuria

40
Q

blood in urine due to muscle damage - Glomerular filtrate

A

myoglobinuria

41
Q

(3) reasons for false positive for blood in urine

A

cleanser- oxidizing contaminant
bacterial peroxidase
menstrual blood

42
Q

(6) reasons for false negative for blood in urine

A
technique errors inadequate mixing of urine sample
formalin preservative
high conc. of ascorbic acid (vit C)
high specific gravity
nitrates
proteins
43
Q

Hematuria is the presence of blood or intact ____ in the urine. A urine that is highly _____ or has a very low ______ can cause the red cells to lyse, thus releasing their hemoglobin into the urine.

A

RBCs
alkaline
specific gravity (1.007)

44
Q

if RBCs lyse in urine, the microscopic exam may show empty RBC membranes called:

A

ghost cells

45
Q

transient hematuria may result from:

A

strenuous exercise

menstrual contamination

46
Q

persistent urine blood (hematuria) may develop with (2)

A
renal diseases (glomerular, tubular, interstitial, vascular)
trauma to kidneys
47
Q

persistent hematuria may be present in patients with

A
urolithiasis (kidney stones)
UTI
urinary tract tumor
bleeding disorders related to anticoagulant therapy prostatic cancer
gynecological disorders
ebola
48
Q

free hemoglobin(hemoglobinuria) may be found in urine if

A
(intravascular hemolysis)
incompatible blood transfusion
hemolytic anemias
immunohemolytic anemias
burns
electric shock
49
Q

myoglobinuria may be due to: (6)

A
rhabdomyolysis
electric shock
myocardial infarction
heroin abuse
alcoholism
after strenuous activity
50
Q

___ & ____ will both produce positive reagent strip blood results because both contain HEME

A

myoglobin

hemoglobin

51
Q

red plasma cells plus red urine =

A

hemoglobin

52
Q

clear plasma cells plus red urine =

A

myoglobin

53
Q

chemical differentiation for myoglobin/hemoglobin in urine

A

based on ammonium sulfate precipitation test

54
Q

amount of bilirubin present in serum in healthy subjects is _____

A

small (less than 10% of total bilirubin)

55
Q

elevated amount of conjugated serum bilirubin implies: (2)

A

liver diseases

cholestatic diseases

56
Q

Unconjugated bilirubin is tightly bound to _____, not filtered by the ____ and absent from urine even with raised serum levels of unconjugated bilirubin.

A

albumin

glomerulus

57
Q

A positive test for urine bilirubin confirms that any raised plasma levels are from

A

conjugated hyperbilirubinemia

58
Q

(2) reasons for false positive urine bilirubin

A

technique errors

atypical color reactions

59
Q

(3) reasons for false negative urine bilirubin

A

large amounts of absorbic acid decrease sensitivity of dipstick
high levels of nitrate
exposure to light and room temperature

60
Q

urine bilirubin confirmation test

A

ictotest

61
Q

urine bilirubin may indicate:

A

gallbladder, blue duct obstruction or liver pathology

62
Q

urobilirubin is ______ color and oxidizes to _____, ____ color

A

colorless

urobilin (brown)

63
Q

10-15% of urobilinogen is ________ and returned to liver, then _____ in intestines

A

reabsorbed in bloodstream

re-excreted

64
Q

normal level or urobilinogen

A

1-4 mg/24 hour period or less than 0.1 Herlich

65
Q

false positive for urobilinogen

A

aspirin
sulfunamides
nitrites
porphyria

66
Q

false negative for urobilinogen

A

use of stale urine
formalin
antibiotics

67
Q

significance of urobilinogen in urine

A

normally present in small amounts
peaks btwn 2-4:00 pm
elevated in liver disease, intestinal obstruction, hemolytic anemia

68
Q

_____ test is a rapid, indirect method for the early detection of significant and asymptomatic bacteriuria

A

nitrate

69
Q

nitrates are present in normal ____, and are _____ soluble and present in ____

A

diets
water- soluble
urine

70
Q

Nitrates converted to nitrites by many bacteria, indicates presence of ____

A

UTI

71
Q

common organisms that can cause UTIs

A
escherichia coli
enterobacter
citrobacter
klebsiella
proteus species
72
Q

to test for UTI caused by NITRITES, urine must have incubated in the bladder for a minimum of ____ , If UTI is caused by only non-nitrate reducers, the reaction will be ___

A
4 hours (usually first morning urine is specimen of choice) 
negative
73
Q

false positive for urine nitrite

A

air exposure to dipstick

74
Q

false negative for urine nitrites (6)

A
specimen containing non-nitrate reducers
insufficient time in bladder
low or no nitrate diet
elevated specific gravity of urine
high level of urobilinogen in urine
ascorbic acid
75
Q

significance for urine nitrite

A

screening method for UTI

76
Q

leukocyte esterase is only present in _____ ; and few ______ seen in urine

A

neutrophils

neutrophils

77
Q

increased # of neutrophils indicates presence of ____

A

UTI

78
Q

screening for UTI includes:

A

neutrophils, pH, protein, nitrite

79
Q

(3) reasons for leukocyte esterase false positive

A

trichomonas infxn
contamination by vaginal discharge
formalin used as preservative

80
Q

(3) reasons for leukocyte esterase false negative

A

high level ascorbic acid
high level protein or glucose
some antibiotics