Introduction to Laboratory Testing Flashcards
(117 cards)
1
Q
use of diagnostic testing?
A
take info from H and P to come up with differential diagnosis
-testing will help guide the diagnostic work up and support your differential dx
2
Q
3 main uses of diagnostic testing?
A
diagnosis, screening, patient management
3
Q
how to decide what to order?
A
- H and P and DDx
- potential benefits vs. costs and disadvantages
- don’t order a test if you don’t know what to do with it**
4
Q
how many diagnostic tests?
A
hundreds for various reasons
5
Q
reference range?
A
use the range of the lab doing the testing
- for 95% of the populations
- 5% population varies outside this range
6
Q
types of common tests?
A
gross pathology, cellular pathology, function, special tests
7
Q
examples of gross pathology diagnostic testing?
A
scopes
x-rays
IVP
spinal myelogram
8
Q
scope
A
visualize organ systems internally
9
Q
x-rays
A
radiation to detect changes in density of tissues, bone and viscera
10
Q
IVP
A
intravenous pyelogram
-view of kidneys, ureters and bladder, usually detect kidney stones, tumors and other blockages in system
**kidney stones
11
Q
spinal myelogram
A
look for spatial changes in spinal canal
12
Q
types of myelograms?
A
IVP and spinal myelogram
13
Q
more advanced x-ray technology?
A
CT scan - x-ray of body tissues that produces slices (cross sections) of an area of the body
-evaluate large areas
14
Q
CT scan
A
with or without contrast**
without contrast- spiral CT of kidneys
with contrast- IV or PO (oral) used to highlight bleeds, small structure in brain, kidneys, spine, and liver
15
Q
contrast used in CT scan?
A
iodine, barium, gastrografin
radioactive agent
-make sure patient has good kidney function**
16
Q
MRI
A
no radiaton**
uses magnetic fields and pulses to give cross sections
can identify masses, tears, bleeding, tissue damage from infection and injury anywhere in body
can be done with or without contrast
17
Q
cellular pathology?
A
biopsy, puncture, FOBT, serum studies, urinalysis, cultures and sensitivies
18
Q
puncture?
A
removal of fluid from area for analysis
19
Q
fecal occult blood test?
A
blood in fecal matter
20
Q
serum studies?
A
routine exam of blood
21
Q
urinalysis
A
exam of urine for cells, tiny structues, bacteria, and chemicals
22
Q
cultures and sensitivities
A
C and S
-growth of an organism from body fluid to identify an organism causing pathology and to identify what is best course of therapy
23
Q
function diagnostic testing?
A
ultrasound and doppler studies
electrograms
angiograms/venograms
24
Q
ultrasound
A
sound waves to detect movement and function of organs
**no radiation
25
doppler studies
sound waves and sonar to detect abnormal blood flow
26
electrogram
test for electrical activity of tissues
EKG or ECG
-electric activity of heart
also nerve conduction studies
27
angiograms/venograms
use dye to detect blockages in arteries and veins
**these are x-ray pictures
28
blood test
analysis on blood sample via venipuncture
-determine physiological and biochemical states
disease, mineral content, drug effectiveness, organ function
also used in drug tests
29
CBC
complete blood count
-cellular components of blood (RBC, WBC, platelets)
values usually correspond to one of many anemias affecting patient
-also correspond with infections and malignancies
30
shorthand of CBC?
left WBC
right platelet
top hemoblobin
bottom hematocrit
31
normal ration of hemoglobin to hematocrit
1/3
32
total erythrocyte range?
4.7e6 - 6.1e6
33
hemoglobin range
female - 12/16 g/dL
| male - 14-18 g/dL
34
hematocrit range
female 37-47%
| male 40-54%
35
hematocrit increase?
high altitude, smoker, tumors
36
hematocrit decrease?
anemia (iron, folate, B12), acute/chronic blood loss, hemolysis
37
hemoglobin increase?
dehydration, burns, vomiting
38
hemoglobin decrease?
all anemias, hypothyroidism, B12 and folate deficiency, chronic disease
39
normal range for WBCs?
4,800 - 10,800 cells/microliter
40
CBC and WBCs?
can be ordered with or without differential**
41
alteration of WBC levels?
infection, inflammation, hemotologic malignancies, leukemias, lymphoma, steroid use, aneimas, drugs, and sepsis
42
left shift of neutrophils?
predominance of immature cells
| -infection, toxemia, hemorrhage
43
right shift of neutrophils?
predominance of mature cells
| -liver disease, anemias, iron deficiency
44
most dominant WBC?
neutrophils (46-80%)
45
lymphocytes
increased in viral disease
| -also acute and chronic lymphocytic leukemias
46
monocytes
increased in bacterial and protozial infection
| -also infections mono
47
eosinophils
increased in allergy and parasites
48
basophils
increased in chronic myeloid leukemia
49
increased in platelets?
after stress
| -trauma and surgical, childbirth, fractures, exercise
50
prothrombin time
assess coagulation pathway
-common for patients on anti-coagulants
normal 11-15 seconds
INR - international normalized ratio
51
normal platelet count?
150,000 - 450,000 microliters
52
warfarin/coumadin?
use PT/INR to asses efficacy of drug
| -reading should be 2-3x normal
53
peripheral blood smear?
stain and scopes viewer can evaluate the size shape and content of blood cells
54
things seen in peripheral blood smear?
macrocytes, schistocytes (helmet cells), howell jolly bodies
55
plasmodium
parasite in malaria
56
microcytic hypochromic
iron deficiency anemia
57
lymphoblasts
elevated levels can indicate lymphoma
58
basophilic stippling
remnants of DNA in RBCs
| -lead poisoning or thalassemia
59
diagnostic by PBS?
plasmodium, microcytic hypochromic, lymphoblasts, basophilic stippling
60
basic metabolic panel
non-cellular elements of blood
| -sodium and chloride
61
sodium
predominant cation in ECF
| creates most osmotic pressure, essential for proper neuron and muscle activity
62
chloride
predominant anion in ECF
affects osmotic pressure of serum
tends to follow sodium
63
increased sodium?
hypernatremia - excessive water loss or sodium injection, loss of ICF fluid characterized by extreme thirst and agitation
64
decreased sodium?
hyponatremia - excessive sweating
- also caused by diarrhea or vomiting
- causes dizziness, confusion, weakness, low BP and shock
65
increased chloride?
diarrhea
66
decreased chloride?
vomiting, DM with ketoacidosis
67
bicarbonate levels?
major buffer of blood when protons are produced by metabolism
used to transport CO2
excretion controlled by kidneys
68
increased bicarbonate
metabolic alkalosis from respiratory acidosis
69
decreased bicarbonate
metabolic acisosis from respiratory alkalosis
70
potassium
predominant cation in cellular fluid
| -changes in serum concentration greatly affects nerve excitation, muscle contraction, myocardial potential
71
increased potassium
hyperkalemia
-renal failure of addisons disease causing weakness, abnormal sensations, cardiac arrhythmias with possible arrest, also in hemolysis of specimin, thrombocytosis, dehydration, massive tissue damage
72
decreased potassium
hypokalemia
| -in diuretics, vomiting
73
increased glucose levels
hyperglycemia in DM
74
decreased glucose levels
hypoglycemia in pancreatic disorders
75
blood urea nitrogen
increased in renal failure or GI bleed
76
creatinine
increased in renal failure, loss of muscle mass
77
normal BUN:Cr ratio
10-20:1
| -used to identify source of dysfunction when values are not in the normal range
78
prerenal?
greater than 20:1
| BUN reabsorption increased, dehydration suspected
79
normal or postrenal
10-20:1
| normal range and also postrenal disease
80
intrarenal
less than 10:1
renal damage causes reduced reabsorption of BUN
81
glucose level measurement?
fasting important**
82
when to use kidney studies?
kidney function OR contrast studies
83
direct vs. indirect bilirubin?
direct is conjugated
| indirect is unconjugated
84
bilirubin
from breakdown of heme
| -insoluble in water, bound to plasma proteins until conjugated with glucuronic acid in liver
85
total bilirubin levels?
less than 0.3 - 1 mg/dL
increased in hepatic damage
86
direct bilirubin?
conjugated
increased in biliary obstruction, dubin johnson, rotor
87
indirect bilirubin?
unconjugated
hemolysis, gilbert, crigler-najjar
88
hemoglobin A1C
accurate measure of average blood sugar over average live of circulating erythrocyte
-approx 6 weeks
now used to diagnose and monitor diabetes control
89
c-reactive protein
acute phase reactant with a short half life
-rises rapidly within 4-6 hours of the onset of inflammation or tissue injury
declines relatively rapidly with resolution, correlates with older very non-specific test called sedimentation rate (ESR)
90
cholesterol
insoluble in water
- carried by lipoproteins
- ingested and synthesized by liver
91
increased cholesterol?
hypercholesterolemia
| -congenital, hypothyroidism, DM, fatty diet and obesity
92
LDL
high levels - accelerated artherogenesis
93
HDL
high levels protective
94
triglycerides
absorbed in blood after fatty meal
- broken down and stored as adipose
- major form of energy at cellular level
- increased levels also associated with accelerated artherogenesis
95
liver profile and liver disease?
all enzymes are increased with liver disease
| -cirrhosis
96
enzymes in liver profile?
```
alanine aminotransferase (ALT)
aspartate aminotransferase (AST)
gamma-glutamyl transferase (GGT)
```
97
alcoholic hepatitis?
AST > ALT
98
viral hepatitis?
ALT > AST
99
thyroid hormone
essential in regulation of metabolism
100
normal urinalysis?
```
normal is clear/yellow
slightly acidic
negative for:
-bacteria, bilirubin, blood, ketone, glucose, protein, intrite, leukocyte esterase (if normal)
trace sediments normal:
-RBC, WBC
```
101
abnormal urinalysis?
- cloudy, foamy, dark yellow/green, red to black, purple to brown
- increased acidity
102
cloudy urinalysis?
pyuria, blood, mucus, bilirubin
103
foamy urine?
proteinuria, bile salts
104
dark yellow or green urine?
bile or bilirubin
105
red to black urine?
RBCs, hemoglobin, myoglobin
106
purple to brown urine?
specimens standing in sunlight from porphyrins
107
increased urine acidity?
infections (proteus), systemic alkalosis, renal tubular acidosis
108
increased specific gravity of urine?
volume depletion
109
decreased specific gravity of urine?
infection, compulsive water drinking
110
bilirubin in urine?
primarily conjugated
| -obstructive biliary tract disease, liver disease
111
blood in urine?
stones, tumors, coagulopathy, infection, menses (contamination)
112
dipstick positive for blood?
no red cells present
-may be free Hg from trauma or a transfusion reaction or lysis of RBCs or there is myoglobin present because of crush injury, burn, or tissue ischemia
113
glucose in urine?
positive in DM
-especially with serum glucose over 200mg/dL
also positive in pancreatitis
114
ketones in urine?
positive in starvation/fasting, diabetic acidosis, vomiting, diarrhea
115
protein in urine?
mostly albumin
| -positive in pyelonephritis, nephrotic syndrome
116
leukocyte esterase in urine
with nitrite test, predictive value for UTI of 74% if both tests positive
117
nitrite test in urine?
positive in infection
