AACC has issued expert guidance on clinical testing for procalcitonin, a blood marker that helps detect serious bacterial infections and sepsis. By giving clinicians and laboratory professionals much-needed clarity on how to best use procalcitonin tests, the new guidelines could improve the treatment of critically ill patients and those with certain lower respiratory infections.
Procalcitonin tests have been used for many years in Europe, but only became available in the United States in 2017, when the U.S. Food and Drug Administration (FDA) approved them as tools to help guide antibiotic treatment and predict which patients are most likely to die within 28 days of being diagnosed with sepsis (also known as 28-day mortality risk). Because procalcitonin tests are relative new in the U.S., there is still confusion about when to use them, and they are often ordered in situations where they are not clinically appropriate.
AACC said that its guidance provides a rigorous examination of the research evaluating procalcitonin along with an analysis of its limitations, with the goal of facilitating better testing and treatment.
“Improved outcomes from [procalcitonin] implementation are more likely to be realized when the test is used in conjunction with antimicrobial stewardship programs, institutional interpretive algorithms, and clinical decision support tools,” the guidance document authors wrote. “Successful implementation of clinical [procalcitonin] requires a multidisciplinary effort among laboratorians, pharmacists, and infectious disease providers.”
Specifically, the guidance document addresses key questions related to the use of procalcitonin to manage adult, pediatric, and newborn patients with suspected sepsis or bacterial infections, or both, and particularly lower respiratory tract infections. It also explores the evidence for using these tests to guide antimicrobial treatment decisions and predict patient outcomes.
Conclusions from the guidance document are as follows:
- Compelling evidence supports the use of procalcitonin testing to help guide clinicians on when to stop antibiotic treatment in critically ill patients and patients with some lower respiratory tract infections. As such, procalcitonin testing should be incorporated into broad antimicrobial stewardship efforts that draw on the expertise of multidisciplinary teams.
- Some studies indicate that procalcitonin levels can also be used to determine when to discontinue antibiotics in newborn and pediatric patients with suspected sepsis who show signs of clinical improvement. However, the guidance authors felt these studies were not large enough to determine standard levels that could be applied across pediatric populations, since the reference intervals for procalcitonin were established in adults. Thus, if procalcitonin testing is used for these groups, the guidance document notes that it’s important to establish pediatric reference intervals or define interpretive criteria.
- In spite of the fact that procalcitonin tests are FDA-approved to predict 28-day mortality risk in sepsis patients, the guidance does not recommend routinely using procalcitonin for this purpose. This is due to a lack of consistent procalcitonin cut-offs and clearance parameters, as well as insufficient evidence demonstrating a benefit to estimating 28-day mortality risk in patients with sepsis and lower respiratory tract infections.
