Term
| What is the ideal goal of a rapid diagnostic test? |
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Definition
| Single step processing with <20 minute results |
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Term
| What are the advantages/disadvantages to traditional staining methods? |
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Definition
A= Rapid and cheap
D= Low sensitivity and not specific |
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Term
| What are the advantages/disadvantages to traditional culture-based methods for bacteria?? |
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Definition
A: High detection sensitivity, more information on identification, cheap
D: Overnight culture, not species-specific |
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Term
| What are the advantages/disadvantages to traditional culture-based methods for viruses? |
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Definition
Ex) IF and cytopathic effect
A: Specific identification (IF especially)
D. Slow, expensive and difficult to grow |
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Term
| What are the advantages/disadvantages to traditional Biochemical identification tests? |
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Definition
Ex) Colony (Catalase, Oxidase, PYR) and Culture (tubes, API strips)
A: species-specific
D: Can be ambiguous with atypical behavior, expensive |
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Term
| What are the advantages/disadvantages to Antigen testing? |
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Definition
Ex) PBP2a agglutination (MRSA); influenza and RSV rapid antigen test
A: Fast compared to viral culture
D: For viral antigens- low sensitivity compared to PCR |
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Term
| What are the advantages/disadvantages to NAAT? |
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Definition
Ex) type IV SCCmec (MRSA), N. gonorrhoea, Chalmydia, HSV; endpoint PCR or rtPCR
A: rapid than culture, very specific and quantitative
D; cost, labor intensive, technically challenging, contamination, not always as sensitive as culture. |
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Term
| What is Rapid TB diagnostic testing and why is it used? |
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Definition
| High sensitivity NAAAT for AFB stain negative cases in the developing world (earlier than culture) |
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Term
| What is Multiplex PCR testing? |
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Definition
1) Respiratory Virus Panel (UPMC) against 12 viruses
2) SeptifFast RT-PCR against 22 bloodstream pathogens (6 hours and 300 CFU/ml) |
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Term
| What is 16S rRNA sequencing and why is it used? |
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Definition
Atypical pathogen behavior!
Primers against sequences flanking variable segments to identify pathogens with isolates that have atypical biochemical phenotypes. |
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Term
| How is MS used in pathogen diagnostics? |
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Definition
1) Vaporization (ion source), Mass:Charge analyzer, Abundance detector
Advantages: speed, generalizability and direct analysis of patient samples
Disadvantages: Overnight culture (Vitex MS), sample prep (PLEX-ID), setup, sensitivity.
- PLEX-ID measure PCR products to identify pathogens by abundance of nucleotides
- Vitex MS: abundant proteins from colonies. |
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Term
| How does pathogen identification by PLEX-ID MS differ from 16S rRNA sequencing? |
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Definition
PLEX-ID measure abundance of nucleotides
16sRNA actually sequences the nucleotides that are their. |
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