Chapter 17- infection diagnosis Flashcards
(39 cards)
Direct fluorescent antibody [DFA]
*highlights the presence of microbes with fluorescently labeled antibodies
*Get antibodies (Y-shaped proteins) and bind them to fluorescent molecules > mix sample with these specific antibodies > microscope slide > Add monoclonal antibody > wash it > if you see glowing bacteria = positive diagnosis
*ex) diagnosing syphilis
Rapid biochemical tests
*[phenotypic analysis]- initial isolation > introduce microbe to various wells on a strip > look at unique color combo reaction > based on this, identify microbe [tests for different metabolic pathways, the material contains assay media/assays]
*Ex) testing for catalase, amylase, TSIA, fermentation of sugars, citric acid fermentation, etc…
*Computers can scan for quick analysis/results
Serology
branch of immunology that deals with in vitro diagnostic testing of serum
Western blot
procedure for separating and identifying antigen or antibody mixtures by 2-d electrophoresis in polyacrylamide gel, followed by immune labeling
*named as a joke from Dr. southerns last name
*use proteins run through a protein gel; antibodies are fluorescentally labeled/ or radiation somehow labeled, placed into paper where proteins were transferred and washed over to see if antibodies bind
*used as verification for HIV after ELISA
ELISA
Enzyme-linked immunosorbent assay; a very sensitive serological test used to detect antibodies in diseases like AIDS
2 types: indirect, capture
rapid biochemical tests analyze:
presence of enzymes
[looking at metabolic pathways]
[NOT involving DNA or antigens]
which test analyzes a sample for the presence of a specific gene?
PCR
All of the following are methods to diagnose viral infections, except
-Western Blot.
-detection of viral nucleic acid using specific probes.
-cells taken from patient are examined for evidence of viral infection.
-signs and symptoms.
-the light microscope.
the light microscope.
Serological tests should have ____ sensitivity and specificity.
high
Tests that take place in the lab, such as in a test tube or Petri-dish, outside of a living host, are referred to as ________ whereas tests that take place in a living host, such as in a patient, are described as ________.
In vitro; In vivo
Serological testing always involves reactions between specific :
antibody and antigen.
The property of a test to detect only a certain antibody or antigen, and not to react with any others, is
specificity.
Some diseases are diagnosed without identification or observation of the microbe itself in a patient’s specimen.
true or false?
true
Which method would allow for direct observation of a specimen?
Gram stain
Soluble antigens are detected in which type of test?
precipitation
The indirect ELISA test detects ________ in a patient’s blood.
antibody
When we describe a test by saying even small or trace amounts of antibodies or antigens can be detected, we are describing its:
sensitivity
A single patient sample can be loaded into multiple PCR tubes to test for different things. The ingredient that would be altered to diagnose for different infections given the same patient sample would be:
the primers
A rising antibody titer a few days apart indicates
the patient has a current infection.
Antigens attached to the surface of cells are detected in which type of test?
agglutination
The tuberculin test is an example of an ____________ test.
in vivo serological
Maggie was told she has a positive antibody titer to measles. Which of the following could explain this?
Any of these V
She had measles sometime in her life.
She was vaccinated against measles.
The test was a false positive.
She has measles now.
Host cells grown in vitro can be used for:
the cultivation of viruses
If trying to isolate a specific pathogen from amongst a variety of normal microbiota, which type of media would be most helpful?
selective and differential agar
