Making an Infection Diagnosis Flashcards
What would be some reasons clinicians wouldn’t use lab results
the speed of progression of infections is much faster than the time taken to generate results
thye do not understand the implications of the data
give me some roles of microbiologist
- provide a clinical consultation service for patients with suspected infection
- clinical advice on the interpretation of results
- advice on therapy
What is the usual circle of events
Patient doctor interaction - differential diagnosis
- clinical specimens
- results
- informed diagnosis
- therapy
What processes can be performed to make such a diagnosis
Direct examination (of sample)
culture
serology
molecular
Advantages of smear diagnosis
- rapid
- simple to perform
- cheap
disadvantages of smear diagnosis
not very sensitive
not very specific
requires considerable expertise
What are the different forms of Light microscopy
Direct (stool-parasites)
Gram (CSF-bacteria)
Z-N (sputum-TB)
Giemsa (blood-malaria)
what can fluorescent microscopy used to diagnose
Respiratory syncytial virus (RSV)
What can electron microscopy be used for
virus detection and indeitification
advantages of culture diagnosis
more sensitive than smear
allows susceptibility testing
allows rapid presumptive diagnosis
allows detailed identification
Disadvantages of culture diagnosis
rendered negative by antibiotics
What is MALDI-TOF used for (advantages)
rapid identification of bacteria
Disadvantages of MALDI-TOF
Does not provide susceptibilities
delayed by slow growth
no value if presence of antibiotics render culture negative
What can serological diagnosis detect
high IgE conc rising of falling titres IgM/IgA Measure avidity (strength) of binding antigen
List me some examples of serological techniques
Agglutination Precipitation Complement fixation virus neutralisation ELISA RIA Immunoflurescence
