Deck 17: Principles of Nucleic Acid Assays for Multiplex Syndrome Panel Testing for the Diagnosis of Infectious Disease

Question 1

What are the two major types of nonculture technology used in many clinical microbiology laboratories?

Answer 1

The nonculture technology is used instead of biochemical tests to identify the organisms that are already grown on culture media.
There are two types of nonculture technology. They are:
• Detection of microbial antigens (antigen detection assay).
• Use of probes to detect microbial nucleic acids (nucleic acid assay).

Question 2

List three advantages of nonculture methods over culture procedures for establishing a laboratory diagnosis of an infectious disease.

Answer 2

The nonculture technology is used instead of biochemical tests to identify the organisms that are already grown in culture.
The advantages of nonculture technology over culture procedures in diagnosing infectious diseases are as follows:
• Nonculture methods can be performed within minutes to hours. Thus, the time for reporting the result can be shortened by the use of nonculture techniques than the culture procedures. The treatment to the patient can be made sooner.
• The evauluations of nonculture methods are reliable than the culture methods as they directly detect the microbial cell structures or products without growing the organism. This will avoid the chances of false-positive results that occur due to the presence of unwanted organisms.
• Nonculture methods are best to detect the infectious agents that cannot be grown in the laboratory conditions. This prevents the transmission of disease.

Question 3

Name three types of immunoassays.

Answer 3

In an immunoassay, an antibody is used to detect the presence of specific microbial antigen.
The three major types of immunoassay that are commonly used are as follows:
• Immunofluorescence
• Latex agglutination
• Enzyme immunoassay (EIA).

Question 4

How does a direct immunoassay assay differ from an indirect assay?

Question 5

What is a "reporter" or "marker" molecule?

Question 6

Name two major types of nucleic acid detection methods.

Question 7

Why are nucleic acid amplification assays more sensitive than nucleic acid probe assays?

Question 8

What is a monoclonal antibody and how does it differ from a polyclonal antibody?

Question 9

What important property of Taq polymerase has allowed its use in the PCR reaction?

Question 10

Briefly define primer, amplicon, and thermocycler.

Question 11

List four major advantages of the use of real-time PCR.