Intro to basic diagnostic and lab testing

Question 1

What are the 3 uses for diagnostic tests?

Answer 1

• establish diagnosis
• screening
• patient management

Question 2

What are the things to consider when ordering a diagnostic test?

Answer 2

• Hx, PE, and DDx should guide tests
• potential benefits vs potential costs and disadvantages
• do you know what to do with it once you get the results

Question 3

What are the categories of common tests?

Answer 3

• gross pathology
• cellular pathology
• function tests
• special tests

Question 4

What allows one to visualize organ systems internally?

Answer 4

scopes

Question 5

What classic gross pathology test uses radiation to detect changes in the density of tissues, including bone a viscera?

Answer 5

x-rays

myelogram is x-ray that uses radioactive dye to detect spacial changes

Question 6

What is a CT scan?

Answer 6

computer tomography scan: x-ray of body tissues that produces “slices” or cross section of an area of the body

Question 7

What gross pathology test uses magnetic field and pulses of radio wave energy to produce computerized pictures (slices) or organs and structures inside the body?

Answer 7

MRI - magnetic resonance imaging

Question 8

What are the 6 types of cellular pathology tests?

Answer 8

biopsies
punctures - removal of fluid from area for analysis
fecal occult blood test (FOBT)
serum studies - routine exam of the blood
urinalysis - routine exam of urine
cultures and sensitivities (C&S) - growth of organism from body fluid to ID

Question 9

What are the 4 general kinds of functional diagnostic tests?

Answer 9

1. Ultrasound - uses sound waves to detect movement and function of organs and tissues
2. Doppler Studies - uses sound waves and sonar to detect abnormal blood flow in arteries/veins
3. electrograms - test for electrical activity of tissues
4. angiograms/venograms - uses dye to detect blockages

Question 10

What specific functional test used x-ray and endoscopy to detect tumors and other blockages in the liver, GB, bile ducts and pancreas?

Answer 10

endoscopic retrograde cholangiopancreatography (ERCP)

Question 11

What specific functional test uses dye and x-rays to detect blockages in the liver and bile ducts?

Answer 11

percutaneous transhepatic cholangiography (PTCA)

Question 12

normal range: RBC, hemoglobin

Answer 12

RBC: 4.7-6.1x10^6th
hemoglobin: (f) 12-16 g/dL, (m) 14-18 g/dL

Question 13

When would hemoglobin be increased? decreased?

Answer 13

increased - dehydration, burns, vomiting

decreased - anemias, hypothyroidism, B12 and folate def, chronic disease

Question 14

When would hematocrit be increased? decreased?

Answer 14

increased - high altitudes, smokers, tumors

decreased - anemia (iron, folate, B12 def) acute or chronic blood loss, hemolysis

Question 15

What does a complete blood count (CBC) include?

Answer 15

total RBC, hemoglobin, hematocrit, WBC and differential, platelet count, prothrombin time (PT), peripheral blood smears (PBS)

Question 16

normal range: WBC, neutrophils

Answer 16

WBC: 4800-10800 cells/microL
Neutrophils:(PMNs) 46-80%

Question 17

Describe “left shift” and when it occurs. what about “right shift”?

Answer 17

left shift - predominance of bands; bacterial infection, toxemia, hemorrhage

right shift - predominance of mature cells; liver disease, megaloblastic anemia, iron def

Question 18

When would each be increased?

lymphocytes, monocytes, eosinophils, basophils

Answer 18

lymphocytes - viral disease, acute and chronic lymphocytic leukemia

monocytes - bacterial and protozoal infections, infectious mono

eosinophils - allergy, parasites

basophils - chronic myeloid leukemia

Question 19

What does a metabolic panel measure?

Answer 19

levels of the noncellular elements of he blood

- fluid, electrolytes, plasma proteins and other constituents