Procalcitonin in critical illness.
OBJECTIVE
To detail the biology and diagnostic usefulness of serum procalcitonin in critical illness.


METHODS
A review of articles published in peer reviewed journals from 1990 to 2001 and identified through a MEDLINE search on procalcitonin.


RESULTS
Procalcitonin (PCT) is a prohormone of calcitonin. Serum levels are elevated during sepsis and have been identified as a potential marker of infection in critical illness. However, its function and precise source of origin during sepsis remain unclear. The value of estimating serum PCT appears to be in the differentiation of infectious from non-infectious forms of systemic inflammatory response syndrome. A number of studies also point to its usefulness in distinguishing between bacterial and viral meningitis. However, there are a number of non-infectious conditions, where elevations in serum PCT occur, reducing its specificity. Its superiority as a marker of sepsis compared with other acute phase reactants continues to be debated.


CONCLUSIONS
The utility of serum procalcitonin as a diagnostic test of sepsis is still under evaluation. Moreover, a number of unanswered questions remain regarding the biological role of PCT during sepsis, its target receptors and its protective value to the patient.
Department of Intensive Care, Royal Brisbane Hospital, Brisbane, Queensland.
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E
O'Connor
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B
Venkatesh
J
J
Lipman
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C
Mashongonyika
J
J
Hall