Exam 5 Diagnostic Studies Flashcards
should you ever make a diagnosis based on labs alone
no
what is over utilization and under utilization
over= ordering too many tests, associated with excessive costs, limited returns, few positives, increase adverse outcomes from studies
under= ordering too few tests
- neg affect pt care
- missed diagnosis
why should you use a diagnostic test
confirm a dx
monitor disease progress/regression
assist in prognosis
monitor drug levels/therapeutic response
measure level of fitness
what are qualitative lab studies
detects whether or not a substance is present
ex: HCG test
what are quantitative lab studies
indicates whether or not present as well as give info about HOW MUCH is present
what are semi qualitative lab studies
detects presence or absence and gives estimations of the concentrations of substance
what are the clinical lab areas
hematology (cell count/blood typing)
clinical chem (electrolytes, enzymes, endocrine)
microbio (culture and sensitivities)
serology (viral tests)
histology / cytology
what is the difference between BMP and CMP
BMP= basic metabolic panel
- 2 renal funciton tests
- glucose
- 2 anions
- 2 cations
CMP= complete metabolic panel
- total protein
- 4 liver assays (albumin, AST, ALK, ALP, bilirubin)
what are included in lytes lab
serum electrolytes
and
anions, bicarbonate, phosphate, cations (Na, K, Mg, Ca)
what are microbiology studies used for
identifying bacteria, fungi, virus, parasite
seeing what organism is susceptible to for treatment: done in both a quantative (disks and semi quantitiative fashion (vials) - for blood CSF etc
aka count and sensitivities
molecular diagnostic studies like assays- costly
ex: PCR, Nucleic acid amplification tests
what is gram stain used for?
fungal culture?
viral culture?
gram stain: rapid info about a bacteria for immediate treatment prior to culture result
fungal: takes 4-6 weeks, then identify fungus and sensitivies
KOH
viral: 7-14 days (with centrifuge = faster),
enhanced takes 1-2 days
what do histology and cytology do
detect the number and types of cells present malignancy, tumor staging, pap smears
also used in blood grouping, matching, etc
what is urinalysis
inexpensive and easy way to get info on kidneys / urinary system
2 stages
- biochemical: go to step 2 if positive
- microscopic - done after centrifuge
name some types of imaging studies
x-ray plain films = most common
CT
MRI
Ultrasound
electrocardiogram
echocardiogram
what appears white (radiodense/radiopaque) in plain films
dense structures like bone
tissue in darker: radiolucent
good for viewing bone, air, fluid filled structures
not good for sof tissues
aka good for
-chest, extremities, abdomen, kidneys, ureters, bladder= KUB, barium swallow
how does a CT work
- what does stand for
- what is it
- how much radiation
- what is used for
Computed tomography
x rays pass through patient and are detected by sensors - analyzed by computer
high radiation= high quality picture
results in precise cross sectional images !!!
NOT a screening tool. Used to make specialized diagnosis
used for specialized Dx: thoracic / mediastinal structures, intraabdominal organs/masses, brain/blood supply, lymp/BVs
how does ultrasound work
- what is it good for
sound waves generate image as move through liquid
- gel= air free barrier
- waves dont pass well thorugh bone
NO radiation
good for repro organs, abd scan, pancreas, aorta, ovaries, appendix, mass, fetus
what does an echocardiography do
ultrasound scanning heart
shows valve function/ blood flow, contraction
use: eval heart murmur, congenital abnormalities, contraction abdnormalities, CHF
how does MRI work
strong magnetic fields and radio frequencies in short pulses
computer translates to image
used for soft tissue, ligaments, tendons, nerves, joints/bones, great for spine/intervertebral discs
CANT use if pt has some metallic implanted device like pacemaker, cardiac valve, metal clips
$$$$
what are nuclear medicine scans
radioisotopes are put into body and taken up by various tissues
the uptake is measure and imaged
excessive uptake = hot spot!!!!!
decreased uptake= cold spots
used to monitor disease progression
what is an electrocardiogram
study of electrical conduction of heart
3-12 leads
detects rhythms, cardiac hypertrophy, myocardial ischemia/injury
indications:
-chest pain, SOB, palpitations, arrhythmias, preoperative screening, fitness screening, HTN, diabetic
MIC
minimum inhibitory conc
done when determining sensitivities of known bacteria/known what kills it
so aka finding right conc to kill
semi quantitative method
vs
quantitative method
semi: done via diffusion, MIC suggestive for diameter away from center of disk
quantitative: dilutional, series of vials used and progressively lower conc of antibiotic
last vial in which no bacteria grow contains antibiotic at MIC
