The rapid and reliable diagnosis of bacterial infection is crucial for three reasons: 1) delays in
the identification of bacteraemia during the first 6 hours after hospital admission are associated with
higher mortality rates; 2) delays in pathogen identification are associated with an increased utilization
of hospital resources (e.g. for ICU treatment); and 3) the treatment of viral illnesses and non-infective
causes of inflammation with antibiotics (because of inaccurate diagnoses) contributes to the
development of antibiotic resistance, toxicity, and allergic reactions, all leading to increased medical
costs. Therefore, the development of rapid and reliable diagnostic tests is an essential prerequisite for
more accurate diagnosis and the effective use of antibiotics within hospitals and general practitioners’
surgeries. One of the most promising technologies likely to impact on rapid and reliable diagnostic
testing involves the flow cytometric quantitative analysis of new specific and sensitive cell surface
markers (receptors) of bacterial infection on phagocytes. As an example of the usefulness of this
method, this chapter presents an outline of how flow cytometric quantitative receptor analysis can be
utilised for the clinical differential diagnosis of hospitalized febrile patients suspected of having an
illness of microbiological origin.
Keywords: Flow Cyometric Aalysis, Phagocytes, CRP/CD11b Ratio, DNAVS Point, Neutrophil FcγRI,
C3, CIS Point Analysis.
