Exam 5 Diagnostic Studies

Question 1

should you ever make a diagnosis based on labs alone

Answer 1

no

Question 2

what is over utilization and under utilization

Answer 2

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

Question 3

why should you use a diagnostic test

Answer 3

confirm a dx

monitor disease progress/regression

assist in prognosis

monitor drug levels/therapeutic response

measure level of fitness

Question 4

what are qualitative lab studies

Answer 4

detects whether or not a substance is present

ex: HCG test

Question 5

what are quantitative lab studies

Answer 5

indicates whether or not present as well as give info about HOW MUCH is present

Question 6

what are semi qualitative lab studies

Answer 6

detects presence or absence and gives estimations of the concentrations of substance

Question 7

what are the clinical lab areas

Answer 7

hematology (cell count/blood typing)

clinical chem (electrolytes, enzymes, endocrine)

microbio (culture and sensitivities)

serology (viral tests)

histology / cytology

Question 8

what is the difference between BMP and CMP

Answer 8

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)

Question 9

what are included in lytes lab

Answer 9

serum electrolytes
and
anions, bicarbonate, phosphate, cations (Na, K, Mg, Ca)

Question 10

what are microbiology studies used for

Answer 10

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

Question 11

what is gram stain used for?

fungal culture?

viral culture?

Answer 11

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

Question 12

what do histology and cytology do

Answer 12

detect the number and types of cells present malignancy, tumor staging, pap smears

also used in blood grouping, matching, etc

Question 13

what is urinalysis

Answer 13

inexpensive and easy way to get info on kidneys / urinary system

2 stages

1. biochemical: go to step 2 if positive
2. microscopic - done after centrifuge

Question 14

name some types of imaging studies

Answer 14

x-ray plain films = most common

CT

MRI

Ultrasound

electrocardiogram

echocardiogram

Question 15

what appears white (radiodense/radiopaque) in plain films

Answer 15

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

Question 16

how does a CT work

• what does stand for
• what is it
• how much radiation
• what is used for

Answer 16

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

Question 17

how does ultrasound work

• what is it good for

Answer 17

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

Question 18

what does an echocardiography do

Answer 18

ultrasound scanning heart

shows valve function/ blood flow, contraction

use: eval heart murmur, congenital abnormalities, contraction abdnormalities, CHF

Question 19

how does MRI work

Answer 19

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

$$$$

Question 20

what are nuclear medicine scans

Answer 20

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

Question 21

what is an electrocardiogram

Answer 21

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

Question 22

MIC

Answer 22

minimum inhibitory conc

done when determining sensitivities of known bacteria/known what kills it

so aka finding right conc to kill

Question 23

semi quantitative method

vs

quantitative method

Answer 23

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