Procalcitonin in intensive care: unresolved doubts

Procalcitonin (PCT), a test marketed by some twenty years, is available virtually on all the platforms present in clinical laboratories of any size, even if its precise role is still debated. PCT is requested especially by intensive care units (ICU) and it has been included in algorithms to guide the administration of antibiotics (AB). However, several reports concluded that, despite a theoretical physio-pathological basis, there is no unambiguous evidence that the inclusion of PCT in algorithms is effective to guide AB treatment. In 2012 the Cochrane Collaboration concluded that "Further high-quality research is needed to confirm the safety of this approach in intensive care. Moreover, future studies should also establish cost-effectiveness by considering country-specific costs of procalcitonin measurement and potential savings in consumption of antibiotics and other healthcare resources, as well as secondary cost savings due to lower risk of side effects and reduced antimicrobial resistance". In 2015, the National Institute for Clinical Heath Excellence concluded that the test is promising but there is still insufficient evidence to recommend its use to guide the AB treatment of sepsis in ICU. Recently, in a paper published in the Clinical Chemistry journal among the limiting factors preventing widespread use of PCT in sepsis and antibiotic stewardship it was included: the limited availability (and high cost) of PCT, the reluctance showed by clinicians to deescalate antibiotics based on PCT results and the uncertainty about the generalizability of previous studies results. The duration of therapy generally tends to be longer compared to what was recommended by guidelines, and PCT-guided antibiotic discontinuation may be of little benefit in hospitals where duration of therapy is already optimized.