What is the role of procalcitonin in COVID-19?

Posted on May 12, 2020 by Lisa Szostek


  • Procalcitonin (PCT) is used as a blood marker for bacterial infections; viral infections generally do not affect PCT levels. 
  • PCT levels have been used to guide decision making regarding when to start and stop antibiotic therapy in patients with acute respiratory infections.
  • Elevated PCT levels may be seen in adult patients with COVID-19. Studies have reported elevated PCT levels in 5.5-35% of cases. Current research indicates that elevated PCT levels are more common in patients with severe disease than with mild disease.
  • Pediatric patients with COVID-19 exhibit more elevated PCT levels than adult patients. PCT elevation seems to be an important laboratory marker in COVID-19 infected children.


  • PCT is a prohormone of calcitonin. The production of PCT is upregulated in the presence of a bacterial infection and it is produced by macrophages and monocytes especially in the liver, lung, and intestines. PCT has cytokine-like behaviour. (1)
  • Procalcitonin (PCT) is used as a blood marker for bacterial infections; PCT rises during bacterial infections and decreases when patients recover. Viral infections generally do not affect PCT levels. (2)


  • PCT can be measured in the blood of patients with a quick turnaround time of 1-2 hours and is used to support clinical decisions in patients with acute respiratory infections regarding antibiotic therapy. Studies have shown the effectiveness of the use of PCT levels to guide treatment for acute upper or lower respiratory infections such as pneumonia, bronchitis, and COPD exacerbations. (3)
  • PCT levels are generally considered elevated if they are >0.05 ng/mL.
  • Reviews have shown the positive use of PCT to guide decision making of when to start and stop antibiotic therapy in patients with acute respiratory infections. The results showed that mortality was lower in PCT-guided patients compared to control patients. Patients with PCT-guided treatment also had a 2.4 day reduction in antibiotic exposure and a reduction in antibiotic-related side effects. Results were similar for types of respiratory infection. (3)


  • The US CDC advises that PCT is typically normally on admission and may increase among those admitted to the ICU. (4)
  • PCT values in pediatric populations appear to be different than those reported in adults. Studies have reported values of 28% and 80% of pediatric patients with COVID-19 showing elevated PCT levels. (5, 6). Despite this wide range in reported elevated PCT levels, PCT elevation is suspected to be an important laboratory marker in COVID-19 infected children. (7)
  • A marked increase in PCT levels has been reported in very severe (mean=0.21) compared with severe (mean=0.05) patients. (8)


  • Other studies that have reported PCT levels in COVID-19 patients are summarized below. Adult patients with COVID-19 more commonly have normal PCT levels than in pediatric populations.
  • A meta-analysis of the four studies reporting clinical characteristics of COVID-19 showed that increased procalcitonin values are associated with a nearly 5-fold higher risk of severe COVID-19. (9)
  • A study looking at clinical characteristics of COVID-19 reported elevated PCT levels in 5.5% of patients (n=633). This was more common in patients with severe disease (13.7%) than in patients with nonsevere disease (3.7%). (10)
  • Another study reported elevated PCT levels  in 8% (n=41) of patients with COVID-19 and 25% of COVID-19 patients in ICU care. (11)
  • Wang et al reported PCT levels >0.05 ng/mL in 35.5% (n=138) of all patients and 75% (n=36) of ICU patients. (12)
  • A study looking at mean PCT level found it to be 0.1 ng/mL (range 0.06 to 0.3 ng/mL) in patients with severe disease and 0.05 (range 0.03-0.1) in patients with nonsevere disease. (13)

Questions? Comments? Does this need to be updated? Do you have valuable points to add ? Please email ask.reakt@ubc.ca.


  1. Moya, F., Nieto, A., R-Candela, J.L. Calcitonin biosynthesis: evidence for a precursor. European Journal of Biochemistry. 1975 July 1. Available from: https://www.ncbi.nlm.nih.gov/pubmed/1201755/
  2. Ruuskanen, O., Lahti, E., Jennings, L.C., & Murdoch, D.R. Viral pneumonia. The Lancet. 2011 April 15. Available from: https://www.sciencedirect.com/science/article/pii/S0140673610614596
  3. Schuetz, P., Wirx, Y., Sager, R., Christ-Crain, M., Stolz, D., Tamm, M., et al. Testing blood procalcitonin levels to decide when to start and stop antibiotics in adults with acute respiratory tract infections. Evidence-Based Child Health: A Cochrane Review Journal [Internet]. 2017 Oct 12. Available from: https://www.cochrane.org/CD007498/ARI_testing-blood-procalcitonin-levels-decide-when-start-and-stop-antibiotics-adults-acute-respiratory
  4. CDC. Interim clinical guidance for management of patients with confirmed coronavirus disease (COVID-19). [Internet, cited 2020 Apr 14]. Available from: https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-guidance-management-patients.html
  5. Xia, W., Shao, J., Guo, Y., Peng, X., Zhen, L., & Hu, D. Clinical and CT features in pediatric patients with COVID-19 infection: different points from adults. Pediatric Pulmonology [Internet]. 2020 May. Available from: https://pubmed.ncbi.nlm.nih.gov/32134205/?from_term=procalcitonin+covid&from_pos=3
  6. Mustafa, N.M., & Selim, L.A. Characterization of COVID-19 pandemic in paediatric age group: A systematic review. Journal of Clinical Virology [Internet]. Available from: https://www.sciencedirect.com/science/article/pii/S1386653220301372
  7. Vakili, S., Savardashtaki, A., Jamalnia, S., Tabrizi, R., Nematollahi, M.H., Jafarinia, M., Akbari, H. Laboratory findings of COVID-19 infection are conflicting in different age groups and pregnant women: A literature review. MedRxiv [Internet]. 29 Apr 2020. Available from: https://www.medrxiv.org/content/10.1101/2020.04.24.20078568v1
  8. Zhou, B., She, J., Wang, Y., & Ma, X. Utility of ferritin, procalcitonin, and C-reactive protein in severe patients with 2019 novel coronavirus disease. Pulmonology [Internet]. 2020 Mar 20. Available from: https://www.researchsquare.com/article/rs-18079/v1
  9. Lippi, G., & Plebani, M. Procalcitonin in patients with severe coronavirus disease 2019 (COVID-19): A meta-analysis. Clinica Chimica Acta [Internet]. 2020 June. Available from: https://www-sciencedirect-com.ezproxy.library.ubc.ca/science/article/pii/S0009898120301066
  10. Guan, W., Ni, Z., Hu, Y., Liang, W., Ou, C., He, K., et al. Clinical characteristics of coronavirus disease 2019 in China. The New England Journal of Medicine [Internet]. 2020 Feb 28. Available from: https://www.nejm.org/doi/full/10.1056/NEJMoa2002032
  11. Huang, C., Wang, Y., Li, X., Zhao, J., Hu, Y., Zhang, L., et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet [Internet]. 2020 Jan 24. Available from https://reader.elsevier.com/reader/sd/pii/S0140673620301835?token=586DEB7882B0E9EF862A2682474892C1D221E07CB27A526BE1B3CEF17712F634F0EB0483E9900CA4C2B229C14F89166A
  12. Wang, D., Hu, B., Hu, C., Zhu, F., Liu, X., Zhang, J., et al. Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus-infected pneumonia in Wuhan, China. JAMA [Internet]. 2020 Feb 7. Available from: https://jamanetwork.com/journals/jama/article-abstract/2761044
  13. Zhang, J., Dong, X., Cao, Y., Yuan, Y.,  Yang, Y., Yan, Y., et al. Clinical characteristics of 140 patients infected with SARS-CoV-2 in Wuhan, China. European Journal of Allergy and Clinical Immunology [Internet]. 19 Feb 2020. Available from: https://onlinelibrary.wiley.com/doi/full/10.1111/all.14238


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