Publication:

Unveiling the role of procalcitonin in COVID-19: a literature review

Procalcitonin (PCT), a key hormone regulating calcium homeostasis, has previously shown the potential to differentiate between bacterial and viral infections. However, when we move further into the field of COVID-19 pandemic, an unprecedented question was raised: Can PCT levels increase without bacterial co-infection in SARS-CoV-2 infection? This review systematically searched PubMed, Scopus, and Google Scholar for articles on procalcitonin (PCT) in the context of COVID-19 published from 2019 to 2023. Inclusion criteria focused on relevant articles, excluding non-English publications. Increasing PCT levels were observed in COVID-19 patients, especially in severe cases, often interpreted as evidence of bacterial co-infection. However, the role of PCT in the immune response to SARS-CoV-2 remains unclear. The proposed mechanisms suggest that SARS-CoV-2 can stimulate the production of PCT even in the absence of bacterial co-infection by modulating the interferon (IFN) pathway and reducing the regulation of monocyte function. Furthermore, PCT has implications in antibiotic management, with guidelines recommended to avoid antibiotics in patients with low serum PCT levels. Increased PCT values show associations with the severity of disease, including increased mortality, which further underlines the need for a detailed understanding of the dynamics of the PCT in COVID-19.  This review emphasizes the evolving significance of PCT in COVID-19, with elevated PCT levels emerging as a valuable prognostic indicator, aiding in disease severity assessment and management. However, the intricate dynamics of PCT in COVID-19 demand further investigation, particularly in distinguishing viral infection from bacterial co-infection.