CICM SAQ 2010.1 Q23

Diagnosis

• PCT is synthesized physiologically by thyroid C cells but in sepsis has extrathyroidal origin from the inflamed/infected tissue
• The biochemical and clinical profile well described
• It is easy to perform (Blood test), not too expensive and provides a quick answer in about 30 minutes. Blood cultures can take up to 24 hours.
• PCT is no gold standard for infection. There number of reports of PCT elevation in non-septic SIRS, immediately after surgery and trauma.
• Data from meta-analyisis are conflicting, some suggesting it is superior to CRP, whilst others have concluded it is a weak biomarker in critical illness.
• PCT is not elevated in viral infection, autoimmune disorders and immunocompromised patients – hence empiric therapy still the way in these
• patients.
• PCT does not tell you the site of infection/inflammation. History, clinical examination and other investigations like CT scan can.
• PCT is a biomarker and cannot replace good history taking, systematic clinical examination, appropriate investigations for the source of sepsis.

Management

• Few prospective randomised studies using PCT as a guide to antibiotic therapy have shown that prescription rate and the cost of antibiotics was reduced significantly with similar outcomes compared to the conventional approach
• Mention of the recent Lancet paper (Jan2010 – ProRata study) and its conclusions is worthy of extra credit