Intro to Diagnosis Flashcards
1
Q
Why use diagnostics?
A
Make REASONED decisions about patient care based on clinical information and estimated outcomes
Used as a screening tool, to assist with diagnosis (urinalysis) and for patient management (measure blood glucose in diabetic)
2
Q
Considerations
A
is it invasive? Is it expensive? Some diagnostics carry a risk of morbidity or mortality
False positives can lead to incorrect diagnosis or further unnecessary testing
3
Q
Criteria used for screening tests:
A
Characteristic of population
characteristic of disease
characteristic of test
4
Q
characteristics of population
A
sufficiently high prevalence of disease
likely to be compliant with subsequent tests and treatments
5
Q
characteristics of disease
A
significant morbidity and mortality
effective and acceptable treatment readily available
pre-symptomatic period detectable
improved outcome from early treatment
6
Q
characteristics of test!
A
good sensitivity and specificity, low cost and risk, confirmatory test available and practical
7
Q
performance of diagnostic tests rely on what two things?
A
patient preparation (fasting, electrolyte restrictions, posture, physical activity prior, compliance)
specimen collection (proper labeling, test timing, medium of collection, proper site and technique [drawing blood above an IV], handling and storage)
8
Q
test characteristics:
A
accuracy
precision
reference interval
interfering factors
sensitivity and specificity
sigma metrics (eh)
9
Q
accuracy (bias)
A
test deemed inaccurate when result differs from true value, even if test is precise, AKA systematic error or bias
10
Q
precision
A
if same specimen is analyzed many times, some variation (random error) is expected
this variability is expressed as a coefficient of variation percentage (CV)
ex: lab reports: serum creatinine with a CV of 5% and accepts results within 2 SD, so if expected result is 1, anywhere from 0.9-1.10 is accepted
11
Q
sigma metrics
A
0-6
3 or less is bad
12
Q
reference intervals in practice
A
(used on tests with quantitative results vs qualitative results)
represent test results found in 95% of a small pop presumed healthy, meaning 5% of healthy pop will have abnormal test result
13
Q
Interfering factors (external and internal)
A
external: certain drugs/meds, contrast media, alcohol/cigs
internal: endogenous antibodies, diet, abnormal physiological states
14
Q
sensitivity and specificity (both independent of prevalence of disease)
A
sensitivity: ability of test to detect disease expressed as % of patients with disease in whom the test was + (true positive vs false positive)
-commonly used for screening
-TP/TP + FN (TP/total diseased)
-vertical math
specificity: ability of a test to detect absence of disease expressed as % of patients without disease in whom test is - (true negative vs false negative)
-commonly used for definitive diagnoses
-TN/TN + FP (TN/total non-diseased)
-vertical math
15
Q
positive predictive value
A
depends on prevalence of test in population
it is the probability of having the disease if test is positive
TP/TP + FP = PPV
16
Q
negative predictive value
A
directly related to prevalence of disease
probably that a person is actually disease free if test is negative
TN/TN + FN = NPV
17
Q
PPV vs NPV (horizontal math)
A
PPV: likelihood of having the disease when the test is positive
- directly related to prevalence
NPV: likelihood of not having the disease when the rest is negative
-inversely related to prevalence
18
Q
prevalence equation
A
total positive/total number of patients x 100
19
Q
methods of blood collection
A
venous, arterial, skin puncture
20
Q
venous puncture
A
primary source of blood collection
most common is antecubital fossa of arm (mainly radial, sometimes ulna if Allen test permits)
basilic, cephalic and median cubital veins, femoral vein
21
Q
venipuncture possible complications
A
bleeding, hematoma, infection, dizziness and fainting
22
Q
arterial puncture
A
used to measure o2, co2 and pH, more difficult, more discomfort, brachial and radial most common used, may use femoral
23
Q
skin puncture
A
Used in pediatric patients: finger tip (capillary), heel (in infants), ear lobes (very vascular)
24
Q
preventing interfering factors
A
hemolysis: don’t shake tubes
Don’t collect from an arm with an IV running
avoid side with lymph node dissection
tourniquet shouldn’t be applied over a min.
25
basic lab tests:
blood chemistries
hematologic data
urinalysis
CSF
Serous body fluids (serous fluid fills body cavities)
26
urine methods of collection:
clean catch, mid-stream, catheter (best option for infection)
-contaminated specimen or true infection? no test is perfect
27
CSF collection
spinal tap
28
other body fluids
pleural (lungs)
peritoneal (abdomen)
synovial (joints)
amniotic
penile/vaginal
29
Blood chemistry tests
BMP: basic metabolic profile/panel
CMP: Complete metabolic profile/panel
-not always necessary! Ruzga would ask why
30
TEST: BMP includes what 8 tests?
Glucose, BUN, Creatinine, Sodium, Potassium, Chloride, Bicarbonate, Calcium (odd man out)
31
CMP includes:
previous 8, albumin, total protein, ALT, AST, ALKP, Bilirubin
focused also on liver function
-Albumin is a major binding protein made by the liver
-bilirubin is waste from red blood cells (that passes through liver before excretion)
32
CBC
complete blood count, helpful in evaluating common symptoms such as weakness, fatigue, fever, bruising
-diagnosing anemia, infection, leukemia, etc.
panel of tests: total WBC, differential, RBC count, hemoglobin concentration, hematocrit, platelet count, MCV, MCH, MCHC, and TDW
-hematocrit=ratio of RBCs to total blood volume
33
WBC
adult normal range: 4.5-11
panic: <0.5
determines total # as well as percentage and absolute # of each type of WBC
34
WBC cont.
Increased in acute (bacterial) infections
-tissue injury/necrosis (tissue death)
-allergies
-stress and smoking
decreased in prolonged (viral) infections (these infections can disrupt WBC production in bone marrow)
-alcoholism
-chemotherapy or radiation
35
TEST: Fives types of WBCs
Neutrophils
Lymphocytes
Monocytes
Eosinophils
Basophils
36
RBC (erythrocytes) normal range
normal range:
males 4.3-6.0
females 3.5-5.5
Increases: hemoconcentration, dehydration
decreases: anemias, cold agglutination
37
TEST: HGB (hemoglobin) normal range:
Males 13.6-17.5 g/dL
females 12.0-15.5 g/dL
panic: <7.0 g/dL
increased in hemoconcentration (essentially water loss): dehydration, burns, vomiting
decreased in liver disease (heme made in liver), b12/iron/folate deficiency
38
TES: HCT (hematocrit) normal ranges
represents percentage of whole blood volume composed of RBCs
males 39-49%
females 35-45%
RULE of thumb: HCT is 3x the HGB value which is x3 the RBC value
39
MCV (mean corpuscular volume) normal range
It is the average volume of the RBCs themselves
used to determine if anemia is microcytic or macrocytic (above average RBC volume)
normal is 80-100 fL
Cleveland clinic: People may develop macrocytic anemia when they don't get enough vitamin B12 and/or folate (vitamin B9) to create healthy red blood cells
40
MCH (Mean corpuscular hemoglobin) normal range
normal range: 27-33 pg
indicates the amount of HGB per RBC in absolute units (picograms, unlike MCHC which relates Hemoglobin content to cell volume)
41
MCHC (mean corpuscular hemoglobin concentration) normal values
normal range: 31-36 G/DL (relates hemoglobin to volume of cell often as %)
determine if anemia is hypochromic, normochromic or hyperchromic
average hemoglobin concentration in RBCs
41
Platelets normal range
released from megakaryocytes in bone marrow and important in hemostasis (repairing vessels)
normal range: 150-450,000/mcL
panic: <25,000
little tendency to bleed until platelet count <20,000
42
when to order platelets
suspected bleeding disorder, evaluating leukemia patients, DIC (clotting disease) monitoring chemo patients, etc.
Leukemia is a broad term for cancers of the blood cells. The type of leukemia depends on the type of blood cell that becomes cancer and whether it grows quickly or slowly. Cancer cells can crowd areas in the bone where platelets are made
43
TEST: PT (prothrombin time) test
evaluates the extrinsic and common coagulation pathways
-extrinsic = tissue damage, endothelial cells release factors
most sensitive to deficiencies in Vitamin K-dependent clotting factors: II, VII, IX and X
-sensitive to factor V
most commonly used for monitoring WARFARIN/COUMADIN therapy
-warfarin is anticoagulant
(not necessary test for preop unless clinically indicated)
44
PTT (partial thromboplastin time) normal range
normal 25-35 seconds
panic >60 seconds (unless using heparin)
evaluates intrinsic and common pathways and adequacy of all coagulation factors (except VII and XIII)
-intrinsic = factors in blood
commonly used to monitor HEPARIN therapy
-heparin is an anticoagulant
45
D-dimer overall!
One of the terminal fibrin degradation products
presence of d-dimers indicates that a fibrin clot was formed and subsequently degraded by plasmin (a proteolytic enzyme [breaks down proteins])
so, d-dimer is elevated whenever the coagulation system has been activated, followed by fibrinolysis
normal range: <400 ng/mL (<0.4)
increased in PE, DVT, VTE, etc. (situations needing clot dissolution)
46
D-dimer cont.
Sensitive test for DIC, DVT and VTE or PE
-exclude DVT/PE in patients with low or intermediate clinical probability
<400 in patients under 50 rules out PE/VTE but positive doesn't confirm diagnosis
-age-adjusted cutoffs now being used to rule out PE
47
urinalysis: what is included
Color, clarity, specific gravity (dehydration, leukocytes [pyuria = WBC in urine], UTI, inflammation), nitrites (infection from bacteria can cause nitrates to become nitrites), blood (trauma in urinary tract, kidney problems, athletes with high activity can cause blood in urine, infection/UTI, bladder cancer [painless hematuria]), ketones (maybe trace amounts normally), protein (kidney failure, preeclampsia, athletes), glucose (not normal, diabetes [injury to kidneys over time due to glucose filtering in kidneys]), microscopic
48
Ruzga's urinalysis advice
Very commonly used to get lots of good info without being invasive, expensive, or if unconvinced patient is really ill
-good for children
49
Body fluids
cell counts and differentials, glucose, protein, albumin, LDH, crystals, gram stain and culture, uric acid
50
BMP cont. (Glucose and BUN)
Glucose: normal 60-110 mg/dL, panic <40 or >500, overnight fasting usually required
-Reduced when insulin increases
BUN (blood urea nitrogen): urea is end product of protein metabolism, excreted by kidney
-BUN is directly related to protein intake and nitrogen metabolism, inversely related to rate of excretion of urea, tests kidney efficiency (increased in renal failure)
-normal range 6-20
51
Creatinine (used with BUN to calculate BUN/CR ratio)
endogenous (produced in body) creatinine excreted by filtration through glomerulus and by tubular secretion
normal range 0.6-1.2 mg/dL
increased in acute/chronic renal failure, nephrotoxic drugs, UT obstruction
-increased creatinine in blood means kidneys aren't working!
not to be used as stand-alone assessment of renal function (GFR should also be assessed)
52
TEST: Sodium
normal range: 135-145, panic <125 or >155
sodium homeostasis crucial for life, predominant extracellular cation, serum Na+ level mainly determined by volume status of individual
-increase in DEHYDRATION. polyuria (frequent urination), steroids/oral contraceptives
53
potassium K+
normal range: 3.5-5, panic <3 or >6
predominantly an intracellular cation, plasma level regulated by renal excretion, plasma levels determine neuromuscular irritability
hemolysis of blood will falsely elevate K level
-"pre-analytical" factors like jarring during transport can cause hemolysis leading to pseudohyperkalemia
-also prolonged use of tourniquet or fist clenching during collection
-also delayed separation of serum from erythrocytes
Anything destroying cells, like injury, elevate K+ levels
Too much potassium stops the heart (death penalty)
If there is too much K+ in blood, you could use different mechanisms to solve the problem. You can shove it into the cell, get rid of it in the gut, flush it out through kidneys with meds (C BIG K DROP)
Insulin will drive potassium into cells
54
chloride (no need for normal range value, not super important)
principal inorganic anion of extracellular fluid
important in maintaining proper body water distribution, osmotic pressure, and normal acid-base balance
partially regulated by the kidneys
test helpful in assessing increased anion gap metabolic acidosis, differentiating causes of hypercalcemia, sweat chloride test used for CF
55
CO2 (important)
essential buffer maintaining pH, venous representation of total bicarbonate, normal range is 22-28, panic is <15 or >40
elevated in metabolic alkalosis
decreased in metabolic acidosis
bicarb increased in: primary metabolic alkalosis // compensated respiratory acidosis
bicarb decreased in: metabolic acidosis // compensated respiratory alkalosis
indicated for all seriously ill patients
56
calcium
prolonged venous stasis during collection causes false increase in serum calcium (aka left tourniquet on too long)
Level of ionized calcium is regulated by parathyroid hormone and vitamin D (TEST)
nothing to do with kidney function
need to also know serum albumin (not on BMP) to interpret total calcium level because it binds to albumin
57
Albumin
major binding protein in the body produced in the liver, influenced by nutritional state, hepatic function
increased in: dehydration, shock, hemoconcentration
indicates severity in chronic liver disease (because liver creates)
58
total protein
plasma protein concentration is determined by nutritional state, hepatic function, renal function, and various disease states
serum protein consists primarily of albumin and globulin (So, when albumin is low, protein is low)
59
AST
intracellular enzyme involved in amino acid metabolism
present in large concentration in liver, skeletal muscle, brain, red cells, kidneys and heart
(!!!) released into blood stream when tissue is damaged, especially in liver injury
decreased in vit B6 deficiency
60
ALT
Intracellular enzyme involved in amino acid metabolism
present in large concentrations in liver
released with tissue damage, especially liver, decreased in Vit B6 deficiency
preferred enzyme for evaluation of liver injury, more sensitive than AST, screening in low-risk pops has PPV of 12% (not recommended)
61
ALKP: Alkaline Phosphatase
primarily found in liver, bone, intestines, kidney, and placenta
used to detect liver disease and bone disorders
(!!) used in measuring the extent of bone metastases in prostate cancer
62
bilirubin
it is orange-yellow pigment derived from the breakdown of hemoglobin (heme)
majority of bilirubin comes from old red cells
biotransformed in the liver and excreted in bile and urine
conjugated form is water-soluble (direct), unconjugated form is fat-soluble (indirect)
-only conjugated bilirubin appears in the urine and it is indicative of cholestatic and parenchymal liver diseases
-hemolysis is associated with increased unconjugated bilirubin
-unbound (free) serum or plasma bilirubin level correlates better than total bili with CNS bili concentrations and bilirubin encephalopathy in newborn jaundice
63
Review of tests
Liver tests: AST, ALT, Bili, ALKP, Total protein, Albumin
-also PT, PTT
bleeding tests: CBC, PT, PTT
kidney tests: BUN, Creatinine
64
WBC differential and ABGs!
Five WBC types
65
Neutrophils
produced in bone marrow, removed through GI tract
Most abundant WBC type, first to arrive in inflammatory response, help to sterilize wound, release protease enzymes to kill potential pathogens but can also cause host damage
increased in normal physiology: severe exercise, pregnancy, labor, surgery, newborn, steroid therapy
increased in pathologic state: bacterial infection, noninfective tissue damage, crush injury, burn, metabolic disorders, leukemia
66
lymphocytes
T: develop in thymus, exported to blood and lymphoid organs (lymph nodes, spleen, etc.)
-cell-mediated cytotoxic reactions
-produce the cytokines that regulate immune responses and provide helper T for B cells
-most common lymphocyte in blood
B: can capture, internalize and present antigens to T cells
-precursors of immunoglobulin-secreting plasma cells
-in marrow, lymph nodes, other lymphoid tissues
NK: effector cell that controls several types of tumors and microbial infections
-innate immunity, best known for killing virally infected cells and detecting and controlling early signs of cancer
67
lymphocytes
Increased in:
-viral infections: AIDS, measles, rubella, mumps, smallpox, flu, hepatitis, etc.
Decreased:
-stress, burns, trauma, HIV and AIDS, MS
68
Basophils
release histamine which is partially responsible for inflammation during allergic reactions
made in bone marrow
allergy testing
heparin is also stored in basophils which may play a role in clotting in the inflammatory response
sudden, massive release of mediators --> reactions in disorder like asthma, drugs, insect stings, other antigens
plays critical role in expression of host resistance to parasites
69
eosinophils
-Non-dividing, end-stage cells originating in marrow from stem
-primarily tissue-dwelling cells in the gut
-Exerts effects through mediators, or chemicals that are either generated new or stored and released due to degranulating stimulus
-plays role in PARASITIC infections
-role in ASTHMA
-Increased in NAACP (Neoplasm, allergy/asthma, addison, collagen, parasites)
-Eosinophilia (increased count) commonly indicates parasitic infection, allergic reaction, or cancer
70
monocytes
-produced in bone marrow
-direct role in sepsis
-poorly defined role in intravascular coagulation and platelet activation
-relatively resistant to viral infections
-increased in bacterial infection, sepsis
71
BUZZ words affecting WBC's
Auer rods (abnormal intracellular body): present in AML (acute myeloid leukemia)
Dohle inclusion bodies: severe infection, burns, malignancy, pregnancy
hypersegmentation: megaloblastic anemia
Toxic granulation: severe illness (sepsis, burn, high fever)
72
ABG (Arterial blood gas)
-Assess the effects of the cardiopulmonary system on oxygen delivery by measuring both oxygenation and ventilation
-directly measure pO2, pCO2, and pH
-mainly obtained to assess ventilation in hospitalized patients
73
ABG includes:
pH
pCO2
HCO3-
pO2
O2 Sat
O2 content
Base excess
alveolar to arterial O2 difference
74
ABG is used for:
-to monitor patients on ventilators
-and monitor critically ill non-ventilators
-establish preoperative baseline parameters
-regulate electrolyte therapy
-(gets back quicker in the ER)
75
PCO2
-partial pressure of CO2 in blood
-measure of VENTILATION
-faster and deeper breathing removes more CO2 and PCO2 drops
-Referred to as the RESPIRATORY component in acid-base determination (primarily controlled by lungs)
76
PCO2 cont.
-PCO2 in blood and CSF is major stimulant to breathing center in brain
-if PCO2 levels rise, breathing is stimulated
-if levels rise too high, breathing cannot keep up (eventually leads to coma)
77
PCO2 cont. (!!)
-elevated in primary respiratory acidosis and decreased in PRAlkalosis
-cuz lungs compensate, PCO2 levels are affected by metabolic disturbances also
-in metabolic acidosis, lungs compensate by increasing ventilation to remove CO2
-In alkalosis, lungs retain CO2
78
HCO3- or CO2 content (!!)
-Most of the CO2 content in the blood is HCO3-
-HCO3- is a measure of the metabolic or renal component of acid-base equilibrium
-regulated by the KIDNEY
-can be measured directly or indirectly by CO2 content in serum
-Do NOT confuse PCO2 (ABG) with CO2 (serum)
79
pO2
-indirect measure of the O2 content of arterial blood
-measure of O2 pressure dissolved in plasma
-this pressure determines the force of O2 to diffuse across the pulmonary alveoli membrane
-decreased in pneumonia, shock lung, CHF/CHD (all O2 diffusion difficulties)
80
O2 saturation
-indication of the % of hemoglobin saturated with O2
-92-100% O2 saturation means tissues are adequately provided with O2 (assuming normal O2 dissociation)
-70% or lower = tissues unable to carry out vital functions
81
alveolar to arterial difference
-A-a gradient (A = alveolar, a = arterial)
-calculated # telling the difference between alveolar O2 and arterial O2
-normal <10mmHg (torr)
-if A-a is high, either problem with O2 diffusing across alveolar membrane or unoxygenated blood mixing with oxygenated blood
82
contraindications to ABG
-no palpable pulse
-cellulitis or open infection at access area
-Allen test is negative, so no ulnar artery
-using radial for access --> possible thrombosis
-AV fistula is present proximal to the site of proposed access
-patient has a severe coagulopathy
83
potential complications
occlusion (blockage/closing) of the artery used for access
penetration of other important structure anatomically close to artery
84
potential complications
occlusion (blockage/closing) of the artery used for access
penetration of other important structure anatomically close to artery
85
interfering factors
-O2 saturation can be falsely increased by carbon monoxide
-In patients with COPD stimulus to breath is not triggered by CO2 levels like normal, but instead O2 levels
-if large amount of O2 is provided to these patients, they won't be driven to breath and will hypoventilate
-respiration can be inhibited by use of narcotics (hypovent)
86
lab methods & standard precautions (SKIM, attention to standard precautions)
lab methods:
Latex agglutination
agglutination inhibition
hemagglutination
electrophoresis
-immunoelectrophoresis
-immunofixation electrophoresis
immunoassay
polymerase chain reaction
fluorescence in Situ Hybridization
87
Latex Agglutination
-latex beads are coated with antibody molecules
-when mixed with a patient's specimen containing a specific antigen, agglutination will be visibly obvious
-alternatively, latex beads coated with antigen and patient's specimen will have antibody
88
Agglutination inhibition
-patient's specimen is incubated with specific target molecule (ex: incubate patient's specimen with anti-HCG)
-latex particles coated with HCG are added to mixture
-if patient specimen has HCG, they will attach to anti-HCG during incubation leaving none to attach to coated latex beads
-therefore, agglutination would not occur and would be + result
88
Agglutination inhibition
-patient's specimen is incubated with specific target molecule (ex: incubate patient's specimen with anti-HCG)
-latex particles coated with HCG are added to mixture
-if patient specimen has HCG, they will attach to anti-HCG during incubation leaving none to attach to coated latex beads
-therefore, agglutination would not occur and would be + result
89
hemoagglutination
-used to identify antibodies to antigens on the cell surface of RBC's
-RBC agglutination is visible
-Used for blood typing
-also can be antigens on RBC surface that are identified
90
electrophoresis
analytic lab method, electric charge applied to medium on which patient's specimen was placed. Migration of charged molecules (particularly proteins) in specimen can be separated, proteins then identified based on rate of migration
91
immunoelectrophoresis (eh)
-allows previously electrophoresed proteins to act as antigens to which known antibodies are added
-provides specific protein identification
-with dilution the proteins can be quantified, used to identify gammopathies, hemoglobinopathies
92
immunofixation electrophoresis
-particularly helpful in identifying certain diseases
-(!!!)helpful in identifying proteins existing in small quantities in serum, urine, or CSF
-A specific known antibody added to previously electrophoresed specimen
-Ag/Ab complexes are fixed to gel medium, non-fixed proteins washed away, protein immune complexes that remain fixed to gel are stained with protein-sensitive stain, can be quantified
93
enzyme-linked immunosorbent assay (ELISA)
-detect antigens or antibodies by producing an enzyme-triggered color change
-plastic bead/plate coated with antigen (virus) and antigen is incubated with patient's serum
-if patient's serum has antibodies to antigen being tested, immunocomplex forms bead/plate
-when chromogenic chemical is added, color change is noted and compared with control
-quantification of abnormal antibodies in patient's serum instigated by viral infection can be performed
-can also be used in reverse, testing for antigen in patient's serum
-used for HIV, hepatitis, or CMVirus
94
autoimmune enzyme immunoassay
-detection of antinuclear antibodies
-EIA techniques similar to ELISA used as purified nuclear antigens are bound to a series of microwells to which patient's serum is serially diluted and added
-after adding up peroxidase conjugated antihuman IgG, a complex of Ab/Ag "sandwich" is identified by color changes
95
chemiluminescent immunoassays
-Extensively used in automated immunoassays
-The chemiluminescent labels can be attached to antibody or antigen
-light emission produced by the immunologic reaction can be measured and quantified
-commonly used to detect proteins, viruses and nucleic acid sequences associated with disease
96
fluorescent immunoassays
-consist of labeling antibody with fluorescein
-this antibody is able to bind either directly with a particular Ag or indirectly with anti-immunoglobulins
-under a fluorescent miscroscope, the fluorescein becomes obvious as yellow-green light
-testing for Neisseria gonorrhea or ANA antibodies may use this method
97
Polymerase chain reaction
in vitro method of amplifying low levels of specific DNA sequences in a patient specimen to raise quantities of potentially present specific DNA sequence to levels that can by quantified for further analysis
helpful in ID of disease caused by gene mutations (BRCA gene mutation)
helpful in ID and quantification of infectious agents (HPV or HIV)
helpful in ID of acquired genetic changes maybe present in hematologic malignancies or colon cancer
97
Polymerase chain reaction
in vitro method of amplifying low levels of specific DNA sequences in a patient specimen to raise quantities of potentially present specific DNA sequence to levels that can by quantified for further analysis
helpful in ID of disease caused by gene mutations (BRCA gene mutation)
helpful in ID and quantification of infectious agents (HPV or HIV)
helpful in ID of acquired genetic changes maybe present in hematologic malignancies or colon cancer
98
PCR cont.
-a known particular target short DNA sequence (100-1000 nucleotides) is used
-known as primer
-primer then placed in series of reactions with a patient's specimen
-reactions are designed to markedly increase number of comparable abnormal DNA sequences potentially existing in specimen
-increased abnormal DNA sequences can then be identified and quantified
99
Fluorescence in situ hybridization
-Uses nucleic probes that are complimentary to the DNA sequence to be identified
-probes labeled with fluorescent tags to identify exact location of complimentary DNA sequence being targeted
-helpful in detection of inherited and acquired chromosomal abnormalities common in hematologic and other oncologic conditions (lymphoma and breast cancer)
100
standard precautions
-all patients should be considered potentially infectious
-applied to all blood, body fluids, and tissues
-applies to sputum, stool and urine only if they contain visible amounts of blood
101
standard precautions cont.
-wear gowns, gloves, protective eyewear, face masks, protective clothing when exposed to blood or body fluids
-if skin is opened, gloves should be worn whenever direct patient care is performed
-mouth to mouth resuscitation equipment should be available in strategic locations
-saliva considered infectious fluid
102
standard precautions cont.
-implement respiratory hygiene/cough etiquette instructions to contain respiratory secretions (for patients with signs of respiratory infection)
-include posting signs with instructions
-offer masks to coughing patients and encourage 3 feet of distance
103
standard precautions cont.
If a worker is exposed to blood or other body fluids, testing of worker and patient for HBV and HIV is necessary
104
REVIEW: Plain Chest X-ray
pneumonia (lateral offers best view), chest trauma (broken ribs), foreign body, pneumothorax, pleural effusion, widening mediastinum
-pneumothorax: collapsed lung
-pleural effusion: buildup of excess fluid between layers of the pleura
105
CT chest without contrast
pneumothorax, foreign bodies (can’t always see object, but could see obstruction from foreign body)
106
CT chest with contrast
Thoracic aortic aneurysm, pneumonia/infections, lung/other cancers, trauma/dissection, tumors
107
CT abd/pelvis without contrast (iodine allergy)
Kidney stones!, bone (If you target lumbar, better image and thinner cuts if focus on that specific area with no contrast)
108
CT abd/pelvis with contrast
infections (any -itis), inflammation, trauma/bleeding (spleen, liver, kidney), free air/perforation (hollow organs: intestines, bladder, stomach, gallbladder), abdominal aortic aneurysm/aortic dissection, tumors
-Vascular, dissections, aneurysms, etc. = contrast!
-dissection: tear in the inner layer of the aorta, very serious
109
CT angiograms
-chest (pulm angio): Pulmonary embolism (VQ backup)
-head/neck/carotid: ischemic stroke (clot blocks artery leading to brain)
-chest/abdominal: coronary angiography, aortic/abdominal aneurysms, dissection
-Extremities: Arterial, decreased blood flow to legs (not doppler US because loss of pulse requires angio)
110
Blood clot vs loss of blood flow (CT vs US)
Clots:
-testes/ovaries: US
-Extremities: US
111
CT head with contrast
Tumor (given IV) (tumors have metabolism and therefore can be noticed with contrast)
112
CT head without
trauma/bleeding (don't want to blend contrast and blood)
113
MRI head
(never for bleeding, because it takes too long and MRI’s are not very sensitive to the vascular system [great at soft tissue, better choice for brain if not related to blood or vasculature])
-MRI in head mostly always with contrast
-Without contrast only in joints and spine (ligament tear in knee for ex.)
-Osteomyelitis: contrast
-MRI can show stroke not due to bleeding (aka ischemic)
(Demyelinating diseases scanned with MRI require contrast!)
114
Brain trauma patient in ER:
-Always start with a CT, if no bleeding but suspected aneurysm, order CT angio
-Never plain x-ray the head, just isn’t worth it
115
Asynchronous pwpt, am i gonna use it?
Not really…
BUT should know standard precautions cuz could be question on that
116
What type of test is used for antigen or antibodies in patient’s serum by using a plastic bead and enzyme-triggered color change?
-ELISA
-enzyme-linked immunoassay
