1. Barlam TF, Cosgrove SE, Abbo LM, et al. Implementing an antibiotic stewardship program: guidelines by the Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America. Clin Infect Dis 2016;62:e51–e77.

2. Cheong HS, Park KH, Kim B, et al. Developing core elements and checklist items for implementing antimicrobial stewardship programs in Korean general hospitals: a modified Delphi survey. Infect Chemother 2023;55:59–68.

3. Biomarkers Definitions Working Group. Biomarkers and surrogate endpoints: preferred definitions and conceptual framework. Clin Pharmacol Ther 2001;69:89–95.

4. Póvoa P, Coelho L, Dal-Pizzol F, et al. How to use biomarkers of infection or sepsis at the bedside: guide to clinicians. Intensive Care Med 2023;49:142–153.

5. Maves RC, Enwezor CH. Uses of procalcitonin as a biomarker in critical care medicine. Infect Dis Clin North Am 2022;36:897–909.

6. Tang BM, Eslick GD, Craig JC, McLean AS. Accuracy of procalcitonin for sepsis diagnosis in critically ill patients: systematic review and meta-analysis. Lancet Infect Dis 2007;7:210–217.

7. Ramírez P, Ferrer M, Martí V, et al. Inflammatory biomarkers and prediction for intensive care unit admission in severe community-acquired pneumonia. Crit Care Med 2011;39:2211–2217.

8. Self WH, Grijalva CG, Williams DJ, et al. Procalcitonin as an early marker of the need for invasive respiratory or vasopressor support in adults with community-acquired pneumonia. Chest 2016;150:819–828.

9. Gewurz H, Mold C, Siegel J, Fiedel B. C-reactive protein and the acute phase response. Adv Intern Med 1982;27:345–372.

10. Póvoa P, Coelho L, Almeida E, et al. C-reactive protein as a marker of infection in critically ill patients. Clin Microbiol Infect 2005;11:101–108.

11. García Vázquez E, Martínez JA, Mensa J, et al. C-reactive protein levels in community-acquired pneumonia. Eur Respir J 2003;21:702–705.

12. Póvoa P. C-reactive protein: a valuable marker of sepsis. Intensive Care Med 2002;28:235–243.

13. Barlam TF, Al Mohajer M, Al-Tawfiq JA, et al. SHEA statement on antibiotic stewardship in hospitals during public health emergencies. Infect Control Hosp Epidemiol 2022;43:1541–1552.

14. Ito A, Shime N, Fujishima S, Fujitani S, Komiya K, Schuetz P. An algorithm for PCT-guided antimicrobial therapy: a consensus statement by Japanese experts. Clin Chem Lab Med 2022;61:407–411.

15. Yoon YK, Kwon KT, Jeong SJ, et al. Guidelines on implementing antimicrobial stewardship programs in Korea. Infect Chemother 2021;53:617–659.

16. Park DW, Choi JY, Kim CJ, Kim JH, Kim HB, Lee DG. Implementation of procalcitonin in antibiotic stewardship: derivation of a consensus algorithm for procalcitonin use in clinical practice. Infect Chemother 2022;54:621–636.

17. Bouadma L, Luyt CE, Tubach F, et al. Use of procalcitonin to reduce patients’ exposure to antibiotics in intensive care units (PRORATA trial): a multicentre randomised controlled trial. Lancet 2010;375:463–474.

18. Layios N, Lambermont B, Canivet JL, et al. Procalcitonin usefulness for the initiation of antibiotic treatment in intensive care unit patients. Crit Care Med 2012;40:2304–2309.

19. Schuetz P, Christ-Crain M, Thomann R, et al. Effect of procalcitonin-based guidelines vs standard guidelines on antibiotic use in lower respiratory tract infections: the ProHOSP randomized controlled trial. JAMA 2009;302:1059–1066.

20. Christ-Crain M, Stolz D, Bingisser R, et al. Procalcitonin guidance of antibiotic therapy in community-acquired pneumonia: a randomized trial. Am J Respir Crit Care Med 2006;174:84–93.

21. Long W, Deng X, Zhang Y, Lu G, Xie J, Tang J. Procalcitonin guidance for reduction of antibiotic use in low-risk outpatients with community-acquired pneumonia. Respirology 2011;16:819–824.

22. Cals JW, Butler CC, Hopstaken RM, Hood K, Dinant GJ. Effect of point of care testing for C reactive protein and training in communication skills on antibiotic use in lower respiratory tract infections: cluster randomised trial. BMJ 2009;338:b1374.

23. Little P, Stuart B, Francis N, et al. Effects of internet-based training on antibiotic prescribing rates for acute respiratory-tract infections: a multinational, cluster, randomised, factorial, controlled trial. Lancet 2013;382:1175–1182.

24. Boere TM, van Buul LW, Hopstaken RM, et al. Effect of C reactive protein point-of-care testing on antibiotic prescribing for lower respiratory tract infections in nursing home residents: cluster randomised controlled trial. BMJ 2021;374:n2198.

25. National Institute for Health and Care Excellence. COVID-19 rapid guideline: antibiotics for pneumonia in adults in hospital. London: National Institute for Health and Care Excellence, 2020. 26. Hessels LM, Speksnijder E, Paternotte N, et al. Procalcitonin-guided antibiotic prescription in patients with COVID-19: a multicenter observational cohort study. Chest 2023;164:596–605.

27. Kiapi G, Gonzalez L, Woodard SL, Urch J. Successful antibiotic stewardship in the electronic era. JAC Antimicrob Resist 2023;5:dlad072.

28. Williams EJ, Mair L, de Silva TI, et al. Evaluation of procalcitonin as a contribution to antimicrobial stewardship in SARS-CoV-2 infection: a retrospective cohort study. J Hosp Infect 2021;110:103–107.

29. Harte E, Kumarasamysarma S, Phillips B, et al. Procalcitonin values fail to track the presence of secondary bacterial infections in COVID-19 ICU patients. Antibiotics (Basel) 2023;12:709.

30. Vanhomwegen C, Veliziotis I, Malinverni S, et al. Procalcitonin accurately predicts mortality but not bacterial infection in COVID-19 patients admitted to intensive care unit. Ir J Med Sci 2021;190:1649–1652.

31. Dolci A, Robbiano C, Aloisio E, et al. Searching for a role of procalcitonin determination in COVID-19: a study on a selected cohort of hospitalized patients. Clin Chem Lab Med 2020;59:433–440.

32. Heer RS, Mandal AK, Kho J, et al. Elevated procalcitonin concentrations in severe Covid-19 may not reflect bacterial co-infection. Ann Clin Biochem 2021;58:520–527.

33. Langford BJ, So M, Raybardhan S, et al. Bacterial co-infection and secondary infection in patients with COVID-19: a living rapid review and meta-analysis. Clin Microbiol Infect 2020;26:1622–1629.

34. Pink I, Raupach D, Fuge J, et al. C-reactive protein and procalcitonin for antimicrobial stewardship in COVID-19. Infection 2021;49:935–943.

35. Houghton R, Moore N, Williams R, et al. C-reactive protein-guided use of procalcitonin in COVID-19. JAC Antimicrob Resist 2021;3:dlab180.

36. Kooistra EJ, van Berkel M, van Kempen NF, et al. Dexamethasone and tocilizumab treatment considerably reduces the value of C-reactive protein and procalcitonin to detect secondary bacterial infections in COVID-19 patients. Crit Care 2021;25:281.

37. Stolz D, Christ-Crain M, Bingisser R, et al. Antibiotic treatment of exacerbations of COPD: a randomized, controlled trial comparing procalcitonin-guidance with standard therapy. Chest 2007;131:9–19.

38. Christ-Crain M, Jaccard-Stolz D, Bingisser R, et al. Effect of procalcitonin-guided treatment on antibiotic use and outcome in lower respiratory tract infections: cluster-randomised, single-blinded intervention trial. Lancet 2004;363:600–607.

39. Mathioudakis AG, Chatzimavridou-Grigoriadou V, Corlateanu A, Vestbo J. Procalcitonin to guide antibiotic administration in COPD exacerbations: a meta-analysis. Eur Respir Rev 2017;26:160073.

40. Butler CC, Gillespie D, White P, et al. C-reactive protein testing to guide antibiotic prescribing for COPD exacerbations. N Engl J Med 2019;381:111–120.

41. Bafadhel M, Clark TW, Reid C, et al. Procalcitonin and C-reactive protein in hospitalized adult patients with community-acquired pneumonia or exacerbation of asthma or COPD. Chest 2011;139:1410–1418.

42. Maisel A, Neath SX, Landsberg J, et al. Use of procalcitonin for the diagnosis of pneumonia in patients presenting with a chief complaint of dyspnoea: results from the BACH (Biomarkers in Acute Heart Failure) trial. Eur J Heart Fail 2012;14:278–286.

43. Demissei BG, Cleland JG, O’Connor CM, et al. Procalcitonin-based indication of bacterial infection identifies high risk acute heart failure patients. Int J Cardiol 2016;204:164–171.

44. Mueller C, Huber P, Laifer G, Mueller B, Perruchoud AP. Procalcitonin and the early diagnosis of infective endocarditis. Circulation 2004;109:1707–1710.

45. Yu CW, Juan LI, Hsu SC, et al. Role of procalcitonin in the diagnosis of infective endocarditis: a meta-analysis. Am J Emerg Med 2013;31:935–941.

46. Picariello C, Lazzeri C, Chiostri M, Gensini G, Valente S. Procalcitonin in patients with acute coronary syndromes and cardiogenic shock submitted to percutaneous coronary intervention. Intern Emerg Med 2009;4:403–408.

47. Remskar M, Horvat M, Hojker S, Noc M. Procalcitonin in patients with acute myocardial infarction. Wien Klin Wochenschr 2002;114:205–210.

48. Schuetz P, Daniels LB, Kulkarni P, Anker SD, Mueller B. Procalcitonin: a new biomarker for the cardiologist. Int J Cardiol 2016;223:390–397.

49. Siriwardena AK, Jegatheeswaran S, Mason JM. A procalcitonin-based algorithm to guide antibiotic use in patients with acute pancreatitis (PROCAP): a single-centre, patient-blinded, randomised controlled trial. Lancet Gastroenterol Hepatol 2022;7:913–921.

50. Cai Y, Ee J, Liew YX, et al. A procalcitonin-based guideline promotes shorter duration of antibiotic use safely in acute pancreatitis. J Infect 2014;69:412–415.

51. Chen L, Jiang J. The diagnostic value of procalcitonin in patients with severe acute pancreatitis: a meta-analysis. Turk J Gastroenterol 2022;33:722–730.

52. Shajiei A, Berends MS, Luz CF, et al. Impact of reduced antibiotic treatment duration on antimicrobial resistance in critically ill patients in the randomized controlled SAPS-trial. Front Med (Lausanne) 2023;10:1080007.

53. Kyriazopoulou E, Liaskou-Antoniou L, Adamis G, et al. Procalcitonin to reduce long-term infection-associated adverse events in sepsis. a randomized trial. Am J Respir Crit Care Med 2021;203:202–210.

54. de Jong E, van Oers JA, Beishuizen A, et al. Efficacy and safety of procalcitonin guidance in reducing the duration of antibiotic treatment in critically ill patients: a randomised, controlled, open-label trial. Lancet Infect Dis 2016;16:819–827.

55. Bloos F, Trips E, Nierhaus A, et al. Effect of sodium selenite administration and procalcitonin-guided therapy on mortality in patients with severe sepsis or septic shock: a randomized clinical trial. JAMA Intern Med 2016;176:1266–1276.

56. Hochreiter M, Köhler T, Schweiger AM, et al. Procalcitonin to guide duration of antibiotic therapy in intensive care patients: a randomized prospective controlled trial. Crit Care 2009;13:R83.

57. Lam SW, Bauer SR, Fowler R, Duggal A. Systematic review and meta-analysis of procalcitonin-guidance versus usual care for antimicrobial management in critically ill patients: focus on subgroups based on antibiotic initiation, cessation, or mixed strategies. Crit Care Med 2018;46:684–690.

58. Sligl WI, Chen JZ, Wang X, et al. Antimicrobial stewardship, procalcitonin testing, and rapid blood-culture identification to optimize sepsis care in critically ill adult patients: a quality improvement initiative. Antimicrob Steward Healthc Epidemiol 2023;3:e107.

59. Borges I, Carneiro R, Bergo R, et al. Duration of antibiotic therapy in critically ill patients: a randomized controlled trial of a clinical and C-reactive protein-based protocol versus an evidence-based best practice strategy without biomarkers. Crit Care 2020;24:281.

60. Oliveira CF, Botoni FA, Oliveira CR, et al. Procalcitonin versus C-reactive protein for guiding antibiotic therapy in sepsis: a randomized trial. Crit Care Med 2013;41:2336–2343.

61. Ali WA, Bazan NS, Elberry AA, Hussein RRS. A randomized trial to compare procalcitonin and C-reactive protein in assessing severity of sepsis and in guiding antibacterial therapy in Egyptian critically ill patients. Ir J Med Sci 2021;190:1487–1495.

62. Yaegashi Y, Shirakawa K, Sato N, et al. Evaluation of a newly identified soluble CD14 subtype as a marker for sepsis. J Infect Chemother 2005;11:234–238.

63. Turgman O, Schinkel M, Wiersinga WJ. Host response biomarkers for sepsis in the emergency room. Crit Care 2023;27:97.

64. Lee S, Song J, Park DW, et al. Diagnostic and prognostic value of presepsin and procalcitonin in non-infectious organ failure, sepsis, and septic shock: a prospective observational study according to the Sepsis-3 definitions. BMC Infect Dis 2022;22:8.

65. Xiao H, Wang G, Wang Y, et al. Potential value of presepsin guidance in shortening antibiotic therapy in septic patients: a multicenter, prospective cohort trial. Shock 2022;57:63–71.

66. Stolz D, Smyrnios N, Eggimann P, et al. Procalcitonin for reduced antibiotic exposure in ventilator-associated pneumonia: a randomised study. Eur Respir J 2009;34:1364–1375.

67. Ogasawara T, Umezawa H, Naito Y, et al. Procalcitonin-guided antibiotic therapy in aspiration pneumonia and an assessment of the continuation of oral intake. Respir Investig 2014;52:107–113.

68. Hellyer TP, McAuley DF, Walsh TS, et al. Biomarker-guided antibiotic stewardship in suspected ventilator-associated pneumonia (VAPrapid2): a randomised controlled trial and process evaluation. Lancet Respir Med 2020;8:182–191.

69. Conway Morris A, Kefala K, Wilkinson TS, et al. Diagnostic importance of pulmonary interleukin-1beta and interleukin-8 in ventilator-associated pneumonia. Thorax 2010;65:201–207.

70. Srinivasan P, Meena JP, Gupta AK, et al. Safety of procalcitonin guided early discontinuation of antibiotic therapy among children receiving cancer chemotherapy and having low-risk febrile neutropenia: a randomized feasibility trial (ProFenC Study). Pediatr Hematol Oncol 2024;41:89–102.

71. Schuetz P, Batschwaroff M, Dusemund F, et al. Effectiveness of a procalcitonin algorithm to guide antibiotic therapy in respiratory tract infections outside of study conditions: a post-study survey. Eur J Clin Microbiol Infect Dis 2010;29:269–277.

72. Hohn A, Heising B, Hertel S, Baumgarten G, Hochreiter M, Schroeder S. Antibiotic consumption after implementation of a procalcitonin-guided antimicrobial stewardship programme in surgical patients admitted to an intensive care unit: a retrospective before-and-after analysis. Infection 2015;43:405–412.

73. Collins CD, Brockhaus K, Sim T, Suneja A, Malani AN. Analysis to determine cost-effectiveness of procalcitonin-guided antibiotic use in adult patients with suspected bacterial infection and sepsis. Am J Health Syst Pharm 2019;76:1219–1225.

74. Gluck E, Nguyen HB, Yalamanchili K, et al. Real-world use of procalcitonin and other biomarkers among sepsis hospitalizations in the United States: a retrospective, observational study. PLoS One 2018;13:e0205924.