Diagnostic Assays in Infectious Disease

Question 1

• the extent to which the test is accurate for those who have the disease in question
• avoiding false negatives

Answer 1

• sensitivity

Question 2

• the extent to which the test is accurate for those who do not have the disease in question
• avoid false positives

Answer 2

• specificity

Question 3

• the extent to which a positive test indicates presence of disease

Answer 3

• positive predictive value

Question 4

• the extent to which a negative test indicates absence of disease

Answer 4

• negative predictive value

Question 5

specimens in light microscopy

Answer 5

• may be fresh or stained

Question 6

sensitivity in light microscopy

Answer 6

• often low

Question 7

specificity in light microscopy

Answer 7

• depends on organisms and specimens

Question 8

sensitivity of culture

Answer 8

• higher than microscopy

- lower than NAATs

Question 9

viral culture requires

Answer 9

• eukaryotic host cells

Question 10

immunoassays involve

Answer 10

• antigens and antibodies

Question 11

formats of Immunoassays

Answer 11

• ELISA
• Western Blot
• Rapid immunochromatographic strip tests
• particle agglutination tests

Question 12

antigen detection test requires

Answer 12

• specific antibodies

Question 13

primary detection antibody recognizes

Answer 13

• same antigen but not same epitope

Question 14

secondary detection antibody recognizes

Answer 14

• Fc portion of primary antibody

- has signal on it

Question 15

indicators of current infection

Answer 15

• antigen detection tests

Question 16

indicators of past infection

Answer 16

• antibody detection tests

Question 17

sensitivity vs specificity most influences test performance in low organism burden

Answer 17

• sensitivity

Question 18

sensitivity vs specificity most influences test performance in potential detection of closely related organisms

Answer 18

• specificity

Question 19

sensitivity vs specificity most influences test performance in too little specimen

Answer 19

• sensitivity

Question 20

sensitivity vs specificity most influences test performance in low prevalence populations

Answer 20

• specificity

Question 21

accuracy

Answer 21

• telling the truth

Question 22

precision

Answer 22

• telling the same story over and over again

Question 23

PPV of highly specific and sensitive test in high prevalence population

Answer 23

• high

Question 24

PPV of highly specific and sensitive test in low prevalence population

Answer 24

• low

Question 25

NAAT

Answer 25

- molecular detection assays for bacteria, viruses, and eukaryotic pathogens

Question 26

NAAT targets

Answer 26

- microbial DNA and RNA

Question 27

NAAT amplification

Answer 27

- enzymatic amplification of target molecules

Question 28

NAAT sensitivity

Answer 28

- more sensitive than microscopy, culture, or antigen detection

Question 29

NAAT specificity

Answer 29

- more specific for nucleotide sequences

Question 30

NAAT live organisms

Answer 30

- doesn't require live organisms

Question 31

NAAT consequences with detection of dead organisms

Answer 31

- impacts timing of test of cure - tests may remain positive for days-weeks after treatment - false positive

Question 32

NAAT increased sensitive allows testing with

Answer 32

- non-invasive pathogens | - using a urine test for STI's instead of endocervical swab.

Question 33

antimicrobial susceptibility testing depends on

Answer 33

- in vitro testing with live organisms grown in presence of antimicrobial agents - culture