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The following is a summary of “ Utility of procalcitonin for identifying secondary infections in patients with influenza or COVID-19 receiving extracorporeal membrane oxygenation,” published in the June 2024 issue of Infectious Disease by Patel et al.

Detecting secondary infections in patients with extracorporeal membrane oxygenation (ECMO)  is challenging as the ECMO circuit affects traditional infection indicators.

Researchers conducted a retrospective study investigating the effectiveness of procalcitonin in diagnosing secondary infections among patients with ECMO with influenza or COVID-19.

They included adult patients who received veno-venous ECMO for underlying influenza or COVID-19 infection (November 2017 to October 2021). Patient demographics, ECMO duration, culture results, and procalcitonin levels were examined. The first procalcitonin measurement was obtained within 3 days of a documented infection compared to procalcitonin levels from patients without infection obtained after 10 days of the most recent positive culture. Additionally, procalcitonin levels were compared across different pathogens and infection sites.

They evaluated 84 patients with ECMO with influenza or COVID-19. A total of 276 procalcitonin measurements were obtained, but only a third, 36% (33 out of 92) of confirmed secondary infections had a corresponding value. Additionally, procalcitonin levels did not differ between infected and non-infected patients (median 1.0 ng/mL IQR: 0.4–1.2) vs. 1.3 ng/mL, IQR 0.5–4.3, P=0.19). While the test showed moderate sensitivity (67%) using 0.5 ng/mL as the cut-off, its specificity for identifying secondary infections was low (30%). A positive procalcitonin result only meant a 14.5% chance of actual disease. Similarly, a negative test had a higher predictive value of 84%. Furthermore, procalcitonin levels did not consistently decline after infection diagnosis, and the pathogen type or infection site did not seem to influence the levels.

Investigators concluded that procalcitonin’s limited accuracy in diagnosing secondary infections in patients with ECMO highlighted the need for alternative diagnostic strategies.

Source: journals.sagepub.com/doi/10.1177/20499361241255873