Intro to Lab Medicine & Common Lab Tests Flashcards

1
Q

Define reference range

A

range of values within a population of people who do not have a given disease
- upper and lower limits
- can vary from lab to lab
- usually central 95%

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2
Q

Define desirable range

A

prognosis related ranges
associate lab results with clinical outcomes - can be a goal rather than a normal result

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3
Q

Define therapeutic range

A

can measure effectiveness of a medication or
screen for possible toxicity

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4
Q

Define laboratory threshold

A

a value that is set to catch presence of disease above a threshold, can result in false positives or false negatives

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5
Q

Sensitivity focuses on a population of individuals who ____ the disease

A

have the disease

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6
Q

Define sensitivity

A

capacity to identify individuals with the disease

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7
Q

Sensitive tests have ____ diagnostic thresholds and specific tests have ____ diagnostic thresholds

A

low (more false positives), high (more false negatives)

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8
Q

Define specificity

A

how effective a test is at correctly identifying people without disease

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9
Q

Specificity focuses on a population of individuals who _____ the disease

A

don’t have the disease

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10
Q

Positive predictive value focuses on people with a _____ test result, negative predictive value focuses on people with a ____ test result

A

positive, negative

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11
Q

Positive predictive value predicts the likelihood that…

A

a positive test identifies someone with the disease (TB test in community with high prevalence)

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12
Q

Negative predictive value predicts the likelihood that…

A

a negative test result identifies someone without the disease (D-dimer)

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13
Q

Define prevalence

A

number of existing cases in a population (expressed as a percent)

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14
Q

Define incidence

A

number of new cases occurring within a period of time (expressed as a number per year)

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15
Q

Reasons for ordering a test

A
  • diagnosing a disease
  • monitoring a disease/interventions
  • screening for a disease
  • research
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16
Q

Questions to ask before ordering a test

A
  • why is it being ordered
  • what are the consequences of not ordering
  • how sensitive/specific is the test
  • how are the results interpreted
  • how will the test results influence patient management
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17
Q

3 phases of the lab testing cycle

A

pre-analytic
analytic
post-analytic

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18
Q

When do most errors occur within lab testing

A

in the pre-analytic phase

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19
Q

Define the rifle approach

A

ordering specific tests based on diagnostic accuracy and predictive value

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20
Q

Define the shotgun approach

A

indiscriminately ordering a large number of tests

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21
Q

What does a pale yellow to amber color urine specimen mean?

A

Normal

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22
Q

What does a straw color urine specimen mean?

A

normal but low specific gravity (hydrated)

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23
Q

What does an amber color urine specimen mean?

A

normal but high specific gravity (dehydrated)

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24
Q

What can colorless urine mean?

A
  • large fluid intake
  • diabetes mellitus
  • diabetes insipidus
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25
Q

What can turn urine orange?

A

Pyridium/AZO

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26
Q

What can turn urine reddish or dark brown?

A
  • blood (RBCs)
  • hemoglobin
  • myoglobin
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27
Q

What does high specific gravity mean

A

dehydration

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28
Q

what does low specific gravity mean?

A

hydrated (also diabetes insipidus)

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29
Q

Low pH means

A

acidic

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30
Q

High pH means

A

basic

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31
Q

Acidic urine can mean…

A

uncontrolled DM - ketoacidosis

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32
Q

alkaline urine can mean…

A

UTI (bacteria strains sometimes)

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33
Q

Hematuria means

A

blood in the urine

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34
Q

Common/Important clinical implications of hematuria

A
  • lower UTI
  • nephrolithiasis
  • urinary tract cancers
  • renal cancers
  • urinary catheter
  • anticoagulants
  • strenuous exercise
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35
Q

Clinical implications of proteinuria

A

kidney diseases

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36
Q

Proteinuria means

A

protein in the urine (mild, moderate, severe)

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37
Q

The presence of _____ in the urine is the single most important indication of renal disease, even in an apparently healthy person if persistent

A

protein

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38
Q

Term for increased urinary glucose is

A

glucosuria or glycosuria

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39
Q

increased glucosuria can mean someone has…

A

diabetes mellitus

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40
Q

Positive urine glucose requires evaluation for which disease

A

diabetes

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41
Q

ketonuria

A

term for increased urinary ketones

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42
Q

clinical implications of ketonuria

A
  • diabetes mellitus (ketoacidosis)
  • starvation/fasting
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43
Q

False positive for urinary ketones can be caused by

A

dehydration and medications

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44
Q

Urine nitrite is a marker for _____

A

bacteria

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45
Q

One interfering factor for urine nitrite is

A

pyridium/AZO (false positive)

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46
Q

Clinical implications of urine leukocyte esterase presence is

A

UTI

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47
Q

False positive for urine leukocyte esterase can be cased by

A

vaginal discharge, infections, contamination

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48
Q

False negative for leukocyte esterase can be caused by

A

pyridium/azo

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49
Q

Increased levels of urinary bilirubin involve this organ

A

the liver

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50
Q

Increased urobilinogen has clinical implications for ____ and _____

A

hemolysis and liver disease

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51
Q

What is the timeframe for urine testing

A

one hour unless refrigerated

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52
Q

What does the presence of casts in urine microscopy indicate?

A

kidney issues

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53
Q

Bacteria in the urine resemble this food item

A

sprinkles

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54
Q

WBCs in the urine resemble this food item

A

cookies

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55
Q

increased WBCs in the urine can be caused by ____, ____, _____, and _____

A

UTI, stones, cancer, inflammation

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56
Q

RBCs in the urine resemble this food item

A

donuts

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57
Q

clinical implications of RBCs in the urine are

A

UTI, renal cancer, bladder cancer, kidney stones

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58
Q

presence of squamous epithelial cells in the urine indicate

A

contamination of the sample

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59
Q

RBC casts indicate_____

A

hemorrhage and are always pathologic
- glomerulonephritis

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60
Q

WBC casts indicate

A

pyelonephritis

61
Q

think ____ disease if there is protein in the urine

A

kidney

62
Q

check for ____ if there is glucose in the urine

A

diabetes

63
Q

blood in the urine requires investigation true or false

A

true

64
Q

positive nitrites and positive LE can mean

A

infection

65
Q

casts are associated with this organ

A

kidneys

66
Q

What medications should be considered when ordering a urine test

A

Vit C and pyridium/AZO

67
Q

CBC means

A

complete blood count

68
Q

What are the 5 things counted in a CBC

A

WBCs
RBCs
platelets
hemoglobin
hematocrit

69
Q

Leukocytes is a term for

A

WBCs

70
Q

leukocytosis means

A

increased WBCs

71
Q

leukopenia means

A

decreased WBCs

72
Q

CBC with differential includes

A

the 5 types of WBCs and the percentage and absolute count for each

73
Q

How many types of WBCs are there

A

5

74
Q

List the types of WBCs

A

neutrophils
lymphocytes
eosinophils
monocytes
basophils

75
Q

What may be indicated in leukocytosis

A

infection or inflammation

76
Q

What med may cause leukocytosis

A

prednisone

77
Q

Causes of leukopenia include

A

viral infections
BAD bacterial infections (sepsis)

78
Q

What is the most numerous WBC

A

neutrophil

79
Q

What WBC is the primary defense

A

neutrophil

80
Q

High neutrophil count is called

A

neutrophilia

81
Q

Causes of neutrohphilia include

A

Bacterial infection, inflammation, steroids like prednisone

82
Q

Neutropenia means

A

low neutrophils

83
Q

Causes of neutropenia include

A

sepsis or viral infection

84
Q

The 3 types if lymphocytes are

A

B cells, T cells, natural killer cells

85
Q

What do lymphocytes do

A

migrate to areas of inflammation

86
Q

Lymphocytosis can be caused by infections like

A

mononucleosis (viral)

87
Q

lymphopenia can be caused by

A

chemo and radiation, AIDS (low T cells)

88
Q

Eosinophils kill invaders with

A

toxic chemicals in granules

89
Q

Think ___ ____ and ____ with eosinophilia

A

wheezes, sneezes and weird diseases

90
Q

Basophils produce ____

A

histamine

91
Q

Basophilia can be caused by

A

inflammation from allergies

92
Q

What is the second line of defense WBC?

A

monocytes

93
Q

monocytosis can be caused by

A

infections and through recovery

94
Q

What do RBCs do

A

carry oxygen to tissue and CO2 back to lungs

95
Q

RBCs use what to carry oxygen

A

hemoglobin (needs iron)

96
Q

Does RBC count differ between men and women?

A

yes

97
Q

define erythrocytosis

A

increased RBC count

98
Q

define erythrocytopenia

A

decreased RBC count

99
Q

One cause of erythrocytosis includes

A

polycythemia vera

100
Q

one cause of erythrocytopenia includes

A

anemia

101
Q

Hgb test checks for _____

A

anemia (differs between men and women)

102
Q

Hct is the ______

A

% of RBCs within entire blood and differs between men and women

103
Q

Hct = Hgb x 3

A
104
Q

Role of platelets

A

blood clotting, vasoconstriction

105
Q

Thrombocytosis

A

increased platelets

106
Q

Thrombocytopenia

A

decreased platelets

107
Q

Thrombocytosis can be caused by

A

cancers (leukemia) and acute infections

108
Q

Thrombocytopenia can be caused by

A

some infections, liver disease (cirrhosis)

109
Q

BMP components

A

sodium, potassium, chloride, HCO3-, blood urea nitrogen (BUN), creatinine, serum glucose, can include calcium

110
Q

What is the primary cation in extracellular fluid

A

Sodium (Na+)

111
Q

Hypernatremia

A

increased serum sodium

112
Q

Hyponatremia

A

decreased serum sodium

113
Q

What is the primary cation in the intracellular fluid

A

Potassium (K+)

114
Q

changes in serum K+ can affect

A

nerves, nuscles, heart

115
Q

Hyperkalemia = ____ potassium, Hypokalemia = ____ potassium

A

high, low

116
Q

If blood sample gets hemolyzed, potassium _____ the cells and can cause a falsely _____ potassium level

A

leaves, elevated

117
Q

What is the primary anion in the extracellular fluid

A

Chloride (Cl-)

118
Q

Hyperchloremia and Hypochloremia

A

high and low chloride

119
Q

Alkalosis = ____ _____, Acidosis = ____ _____

A

increased bicarbonate, decreased bicarbonate

120
Q

Increased BUN can mean

A

kidney insufficiency, urinary tract obstruction

121
Q

Decreased BUN can mean

A

low protein diet

122
Q

Elevated creatinine means decreased ____ function

A

renal

123
Q

Does creatinine differ in men and women

A

yes

124
Q

Should the glomerular filtration rate be lower or higher

A

higher, low = bad

125
Q

What is the glomerular filtration rate

A

how well the kidneys are working

126
Q

What can a GFR be part of?

A

BMP

127
Q

Anion Gap (AG) tells diference between

A

serum cations and anions

128
Q

serum glucose can be caused by

A

diabetes and severe infection and steroids

129
Q

hypoglycemia and hyperglycemia refer to ____ ____

A

serum glucose

130
Q

Hypercalcemia is associated with

A

heart problems

131
Q

hypocalcemia is associated with

A

muscle contractions, seizure

132
Q

increased serum calcium is associated with

A

hyperparathyroidism (bone breakdown), too much Vit D

133
Q

decreased serum calcium is associated with

A

hypoparathyroidism, Vit D deficiency

134
Q

Hgb A1C tells us what

A

average blood sugar over past 6-12 weeks and tests for diabetes mellitus

135
Q

What can confound Hgb A1c

A

pregnancy

136
Q

Increase serum amylase is associated with

A

pancreatitis

137
Q

decreased serum amylase is associated with

A

pancreatic insufficiency

138
Q

increased serum lipase is associated with

A

pancreatitis

139
Q

Increased serum AST (aspartate aminotransferase) is associated with

A

liver problems

140
Q

Increased serum ALT (alanine aminotransferase) is associated with

A

liver damage

141
Q

increased serum alkaline phosphatase is associated with

A

liver problems

142
Q

decreased alkaline phosphatase is associated with

A

osteoporosis

143
Q

What is a CMP

A

comprehensive metabolic panel

144
Q

What is included in a CMP

A

everything on a BMP pluse
AST
ALT
Alk phos
Bilirubin
total protein
albumin

145
Q

BMP includes (list)

A

Na
K
Cl
HCO3
BUN
Cr
Glucose
Ca

146
Q

CMP includes (list)

A

Na
K
Cl
HCO3
BUN
Cr
Glucose
Ca
ALT
AST
Alk phos
Bilirubin
total protein
Ablumin

147
Q

Serum GGT (gamma-glutamyl transferase) can test for

A

liver problems (not included in CMP/BMP)

148
Q

Examples of POCT (point of care testing)

A

fingerstick glucose
urine preg
rapid strep
Hgb A1c