Febrile Antigens

Question 1

stained bacterial antigen suspensions used to identify and measure antibodies following infection

Answer 1

febrile antigens

Question 2

the bacteria cause the body to produce the antibody in response to what

Answer 2

pathogens created

Question 3

what is the positive reaction when serum sample is mixed with a febrile antigen?

Answer 3

agglutination

Question 4

serologic tests performed when dealing with febrile antigen

Answer 4

widal test, weil-felix test

Question 5

specifically for the detection of antibodies from typhoid

Answer 5

widal test

Question 6

what is the causative agent of typhoid?

Answer 6

salmonella enterica subsp. enterica serovar typhi

Question 7

test specifically for the detection of antibodies for Rickettsial infection

Answer 7

Weil-Felix test

Question 8

what is used in Weil-Felix test as bacterial suspension

Answer 8

Proteus

Question 9

for the widal test, what are the 4 antigen suspensions used?

Answer 9

s. typhi O
s. typhi H
s. typhi BH
s. typhi AH

Question 10

what is the negative control for the widal test?

Answer 10

normal saline solution

Question 11

in weil-felix test, what are the 3 antigen suspension used?

Answer 11

Proteus OX2
Proteus OX19
Proteus OXK

Question 12

Proteus associated with P. vulgaris

Answer 12

Proteus OX2

Question 13

Proteus associated with P. mirabilis

Answer 13

Proteus OX19

Question 14

Proteus associated with Kingsbury strain

Answer 14

Proteus OXK

Question 15

what is utilized as an antigen in Widal test?

Answer 15

killed salmonella typhi

Question 16

where does the salmonella typhi grow?

Answer 16

intestines, blood

Question 17

mode of transmission of typhoid

Answer 17

eating or drinking food or water contaminated with feces of an infected person

Question 18

what are the dominant antigens that we deal with in widal test?

Answer 18

antigen O, antigen H

Question 19

somatic antigen
heat stable

Answer 19

antigen O

Question 20

flagellar antigen
heat labile

Answer 20

antigen H

Question 21

what is the sample of choice in widal test?

Answer 21

serum

Question 22

what vacutainers are used for the specimen of widal test?

Answer 22

non-additive vacutainer (red or yellow top)

Question 23

what drug is taken by the patient while waiting for the result of the Widal test and cultures of blood and stool

Answer 23

chloramphenicol

Question 24

Vi antigen (capsule/ virulence)
thermolabile, unstable, delicate

Answer 24

K antigen

Question 25

among all the antigens of S. typhi, what is used for reference laboratories?

Answer 25

K antigen

Question 26

is the positive result of rapid slide screening method an indication of S. typhi infection?

Answer 26

no

Question 27

enumerate the degree of agglutination for widal rapid slide titration method

Answer 27

4+ 100% (solid clumps) 3+ 75% 2+ 50% 1+ 25% Trace less than 25% Negative no agglutination

Question 28

(WIDAL'S TEST rapid slide titration) serum volume and approximation tube dilution

Answer 28

0.08ml 1:20 0.04ml 1:40 0.02ml 1:80 0.01ml 1:160 0.005ml 1:320

Question 29

all positive results obtained through the slide test should be confirmed using the following technique

Answer 29

Widal's tube agglutination test

Question 30

incubation time and temperature in water baths for salmonella "O" antigens and proteus

Answer 30

50C for 4 hours

Question 31

incubation time and temperature in water baths for salmonella "H" antigens and proteus

Answer 31

50C for 2 hours

Question 32

antibody excess

Answer 32

prozone

Question 33

antigen excess

Answer 33

postzone which causes negative test result

Question 34

characterisitc of positive result in widal's tube agglutination test

Answer 34

obvious floccular agglutination throughout the tube

Question 35

considered significant titer in the widal's test

Answer 35

1:80

Question 36

considered significant titer for weil-felix test

Answer 36

1:160

Question 37

what causes a stronger agglutination reaction which is not easily dispersed between the types of agglutination test in widal's

Answer 37

somatic agglutination

Question 38

fluffy and floccular aggregates that are easily dispersed

Answer 38

flagellar agglutination

Question 39

significant titer for flagellar agglutination

Answer 39

greater than 80 = indicates infection

Question 40

indicates acute/recent typhoid fever

Answer 40

INC titer on OD Ag

Question 41

indicates acute/recent paratyphoid infection

Answer 41

INC titer on OA, OB, OC

Question 42

indicates previous/ past infection with typhoid fever convalescent/vaccination against typhoid fever

Answer 42

INC titer on HD Ag

Question 43

indicates past infection on S. paratyphi

Answer 43

INC titer on HA, HB, HC

Question 44

indicates mixed infection

Answer 44

INC titer on O and H Ag

Question 45

what causes typhus fever?

Answer 45

R. prowazekii

Question 46

what is the mechanism used in weil-felix test

Answer 46

cross reaction mechanism

Question 47

why does weil-felix test use proteus?

Answer 47

because of the cross-reaction mechanism; rickettsia and proteus possess the same antigenic determinants