unit 5

Question 1

serology

Answer 1

study of blood serum (blood without clotting factor)

Question 2

titer

Answer 2

tells us concentration based on dilution of blood

Question 3

evaluate storage conditions for specimens received in laboratory for serologic diagnosis of infectious diseases

Answer 3

refrigerate up to 1 week then freeze at 20 degrees celsius

Question 4

factors that affect antigen-antibody reactions

Answer 4

specificity, accessibility (able to detect), valency (# of binding sites), antibody structure (dimers etc.), concentrations (zone of equivalence), affinity (strength), avidity (capacity)

Question 5

categories of serologic tests used to diagnose human disease

Answer 5

pricipitation, agglutination, etc.

Question 6

principles of precipitation tests

Answer 6

soluble antigen and antibody bind in equal proportion to form insoluble immune complexes (this is what we measure)

Question 7

postzone vs prozone

Answer 7

prozone –> antibody excess
postzone –> antigen excess

Question 8

interpretation of the ouchterlony test

Answer 8

formation of three possible precipitant lines

arc (identity) –> identical Ag
spur (partial) –> common epitope)
intersect (non) –> unrelated Ag

Question 9

fahey vs mancini quantitative assays

Answer 9

fahey (kinetic) –> standard curve to extrapolate; 18hrs

Question 10

immunoelecrophoresis vs immunofixation

Answer 10

in immunofixation (more specific) you run sample in multipe lanes instead of just one

Question 11

immunoblots vs dot blots

Answer 11

immunoblots: harder to read, electrophoresis performed to separate

dot blots: easier to read, electrophoresis not performed

Question 12

nephelometry

Answer 12

measurement of light scattered by immune complexes
(more sensitive)

Question 13

turbidimetry

Answer 13

measurement of light transmitted through immune complexes

Question 14

chemiluminescence

Answer 14

chemical reaction that produces light –> on labeled Ab

Question 15

flocculation test

Answer 15

used for syphilis testing
soluble antigen and antibody form precipitate –> small clumps of charcoal if Ab is present

Question 16

direct agglutination

Answer 16

patient Ab binds to Ag found in bacteria

Question 17

passive agglutination

Answer 17

antigen is artificially added to latex and will bind to patients Ab

Question 18

reverse passive agglutination

Answer 18

antibody is artificially added to latex and will bind to patients Ag

Question 19

agglutination inhibition tests

Answer 19

competition between precipitate and antigens for limited antibody sites
–> test antigen with patient serum, if no precipitate that means there are antibodies present

Question 20

agglutination vs precipitation reactions

Answer 20

A: insoluble antigen; qualitative test
P: soluble antigen and antibody; qualitative and quantitative

Question 21

direct vs indirect fluorescence assays

Answer 21

D: detect antigens in tissue when labeled antibody bind and show as fluorescent under microscope

In: detect unlabeled antigens using patients serum to bind if present and then labeled antibodies to bind to patients antibodies

Question 22

principle and uses of flow cytometry

Answer 22

quantitative method that sorts cells telling us its size, components and identity
–>cells come down flow cell in single file, pass laser, and detectors sort

Question 23

principles of labeled tests

Answer 23

enzyme attached to antibody, when binds and enzymatic change occurs there is a color change to signify positive test

Question 24

mechanisms of how heterophile antibodies can affect immunoassays

Answer 24

heterophiles will bind to capture antibodies blocking binding sites

Question 25

methods to minimize interference by cross reactive antibodies

Answer 25

dilution to ensure 1 antigen binds to multiple Abs
–> monoclonal ab (specificity)

Question 26

conjugated antibody

Answer 26

labeled antibody with fluorescence

Question 27

sensitivity

Answer 27

ability to correctly identify disease

Question 28

specificity

Answer 28

ability to correctly identify patients that do not have disease

Question 29

negative predictive value

Answer 29

measure of how likely a negative test result actually means no disease

Question 30

positive predictive value

Answer 30

measure of how likely positive test result actually means there is disease

Question 31

true positive

Answer 31

actual postive result

Question 32

false positive

Answer 32

positive result that is actually false

Question 33

true negative

Answer 33

negative result that is correct

Question 34

false negative

Answer 34

negative result that is actually positive