Principles of Infectious Disease III: Techniques and Testing Flashcards Preview

Foundations Week 3 > Principles of Infectious Disease III: Techniques and Testing > Flashcards

Flashcards in Principles of Infectious Disease III: Techniques and Testing Deck (16):

What are the eight essential types of specimens?

- plasma
- fluid
- biopsies
- blood
- tissue
- urine
- swabs in general are not good specimens. may swab throat for respiratory virus
- sputum is a poor sample


What are the three essential diagnostic tests?

- amplified nucleic acid techniques
- stains
- bacterial culture


What are the seven types of stains (diagnostic tests)?

- gram stain
- acid-fast bacteria stain
- fungal stains
- parasitology stains
- vital stains (acridine orange)
- antibody to antigens
- nucleic acid probes


What are two types of bacterial culture (diagnostic tests)?

- protein-based, genotype, or phenotype identification
- agar and antibiotics discs, broth dilution


What are two types of antimicrobial testing?

- susceptibility to antibiotics
- agar and antibiotics discs, broth dilution


What are the key interactions and relationships between clinicians and clinical microbiology and epidemiology, for pre-analytical, analytical and post-analytical issues?

- determine appropriate patients for culture
- choose appropriate specimen for culture
- read the test results correctly
- treat appropriately based on test results


What are the general approaches to laboratory diagnosis of infection?

- obtain a specimen from infected site
- use appropriate procedure for the pathogen (stain specimen, observe if bacteria are present and determine morphology, gram +/-, and whether single or multiple pathogens are present)
- culture the specimen on appropriate media to obtain a pure culture. Incubate in presence or absences of oxygen as appropriate
- perform antimicrobial susceptibility tests


What are the important steps that precede laboratory workup?

- choosing appropriate specimen to examine
- obtaining specimen properly to avoid contamination from normal flora
- transporting the specimen promptly to the lab or storing it correctly
- providing any essential information to the lab to guide the laboratory diagnosis


What are the three types of specimen collected?

- direct
- indirect
- sample from site with normal flora


What are types of direct specimen?

Specimens collected form normally sterile tissues or body fluids
- lung, liver, blood, CSF


What are types of indirect specimen?

Specimens that have passed through sites that aree known to be colonized by normal flora
- specimens that are inflammatory exudates
--> urine or expectorated sputum


What are types of specimen collected from sites with normal flora?

- large intestine
- pharynx
- oral cavity
*primarily an issue with bacterial diagnosis since they dominate makeup of normal flora; less of an issue with viral flora, there is little viral normal flora


What are direct methods for diagnosing pathogens?

- wet mounts


What are routine culture tests?

- isolation and ID of bacteria and fungi
- isolation and ID of viruses


What are serologic methods?

Serology methods include:
- antibody detection whereby antigen preparations are used to detect circulating antibodies as evidence of a current or previous infection
- antigen detection where antisera is used to detect circulating antigens


What are nucleic acid amplification tests?

Polymerase Chain Reaction (PCR) is most commonly used NAAT