Procalcitonin is likely one of the most misunderstood laboratory tests in our armory of diagnostics. For many it is viewed as a holy grail for determining if an infection is bacterial, and thus requires antibiotics, or viral, and thus needs supportive care. As an emergency physician, I am constantly asked to order this test - lets looks look at the studies to see how it may be useful.
In 2006 in Critical Care Medicine it was shown to likely be superior to WBC and CRP for predicting mortality, however, when studies again in 2010 by Critical Care Medicine in a meta-analysis of 7 randomized clinical control trials, it did not demonstrate any difference in mortality, however, did results in overall 4 days less antibiotic use on average. The journal Shock in 2008 published a small study in a non - U.S. site which suggested that procalcitonin was superior to CRP for predicting mortality. The FDA approved its use based on this when used in conjunction with other indicators at a cutoff of < 0.5 being low risk, and > 2 being high risk.
The Cochrane collaboration in 2012 showed that there was again no different when procalcitonin was used and the confidence intervals demonstrated to statistical significance.
In 2006 in Critical Care Medicine it was shown to likely be superior to WBC and CRP for predicting mortality, however, when studies again in 2010 by Critical Care Medicine in a meta-analysis of 7 randomized clinical control trials, it did not demonstrate any difference in mortality, however, did results in overall 4 days less antibiotic use on average. The journal Shock in 2008 published a small study in a non - U.S. site which suggested that procalcitonin was superior to CRP for predicting mortality. The FDA approved its use based on this when used in conjunction with other indicators at a cutoff of < 0.5 being low risk, and > 2 being high risk.
The Cochrane collaboration in 2012 showed that there was again no different when procalcitonin was used and the confidence intervals demonstrated to statistical significance.
If you look at the mortality and treatment failure data, procalcitonin was not a clinically or statistically significant indicator of either of these outcomes. Thus, the early studies were hopeful that this would be a useful tool in early identification of sick patients with bacterial illness, better than CRP and WBC - however, in larger trials, it doe snot show any difference in mortality outcomes or treatment failures. It may help decrease the duration of empiric antibiotic therapy. Its use is now recommended by the surviving sepsis campaign for the reduction in empiric antibiotic therapy course duration in admitted patients.
Hopefully we will have a magic test in the future that will clearly distinguish between bacterial and viral sources of infection, however, in the meantime... keep using your clinical gestalt.
Hopefully we will have a magic test in the future that will clearly distinguish between bacterial and viral sources of infection, however, in the meantime... keep using your clinical gestalt.
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