Lab exam 2

Question 1

ELISA detects what

Answer 1

antigen or antibody depending on how designed

Question 2

How does ELISA work

Answer 2

96 well plate lined with antigen or antibody. Patient sample added- if there are antigen/antibody present will bind. Wells washed and then color reagent added

Question 3

is ELISA quantitative or qualitative

Answer 3

inherently quantitative but can be qualitative depending on how light or dark color is

Question 4

virus isolation is a technique used to recover __

Answer 4

live virus from patient sample by growing it in susceptible cell lines

Question 5

what sample types are commonly used in virus isolation

Answer 5

spleen or lung homogenates, placental or seminal fluid, CSF

Question 6

in virus isolation cell cultures are grown until they reach confluence what is that

Answer 6

mature though still actively dividing

Question 7

what is virus isolation evaluating for

Answer 7

cytopathic effects

Question 8

what cytopathic effects are being looked for

Answer 8

cells ball up, cells become spindle shaped, form inclusion bodies

Question 9

virus isolation- which one shows cytopathic effects A or B

Answer 9

B

Question 10

what is serum neutralization assay

Answer 10

antibody titration test

Question 11

what are the 3 key materials in serum neutralization assay

Answer 11

1. Cells growing in cell culture
2. Specific virus
3. Patients serum

Question 12

how does serum neutralization assay work

Answer 12

1. Susceptible cells grow in 96 well plate
2. Serially dilute patient serum 1:40, 1:80 and 1:160 And on. If antibodies are present they would be highest concentration in 1:40 and lowest at 1:5120
3. Virus is added to wells at constant concentration.
4. Incubate and let infect cells
5. Cells checked for cytopathic effects
6. If there are enough antibody present, it will bind viral particles and they will not be able to infect the cells

Question 13

how do you interpret the serum neutralization assay

Answer 13

1. First well with 1:40 highest antibody concentration- enough to prevent virus- no cytopathic effects
2. As gets more dilute antibody concentration goes down

Question 14

serum neutralization assay: Patients with a 1:40 titer have a low level of antibodies are likely ___ or ___

Answer 14

Not infected or never been vaccinated

Question 15

Serum neutralization assay: high level of antibody could be due to __, ___ or __

Answer 15

active infection, previous infection, previous vaccination

Question 16

how do you re-evaluate serum neutralization assay to determine if active infection if there is high antibody level

Answer 16

check in 2 weeks to see if antibody titer has changed, if it has gone up likely active infection

If it has gone down or unchanged likely hx exposure or vaccine

Question 17

Use a __fold rise in tigers when evaluating an active infection

Answer 17

4

Question 18

is serum neutralization assay quantitative or qualitative

Answer 18

quantitative

Question 19

define morbidity

Answer 19

patients in diseased or disabled state

Question 20

define prevalence

Answer 20

testing for whether or not cases have been exposed or infected

Question 21

define morbidity rate

Answer 21

either the incidence or prevalence of disease in a population

Question 22

define mortality rate

Answer 22

measurement of the number of deaths due to a given infectious agent in a population per unit of time

Question 23

define case fatality rate

Answer 23

considers the mortality rate only among those who are affected, not total population