Relative importance of inflammatory markers in deciding infection versus inflammation

Subroto Chakrabartty, Ajit Sardar, Aniruddha Ghosh, Santanu Barman


Background: Fever is the commonest presentation of pediatric patients attending emergency departments of all children’s hospital. The cause of fever may be acute bacterial infections or primary vasculitic disorders like Kawasaki disease or inflammation due to non-bacterial infections. The objective was to compare the performance of the four biomarkers ESR, CRP, Procalcitonin and IL-6 in predicting a diagnosis of sepsis/infection and find out a definite cut off value for the statistically most significant one.

Methods: The authors conducted this prospective observational study at the indoors of a pediatric tertiary care referral center in India to find out a biomarker which can differentiate between infection and inflammation (vasculitis) in children admitted with fever and finally diagnosed as infection or inflammation (vasculitis).

Results: Among ESR, CRP, Procalcitonin and Interleukin-6, only IL-6 showed statistical significance in differentiating infection from inflammation (vasculitis) analysed using the Receiver Operating Characteristic (ROC) curve and Mann-Whitney U test, sensitivity and specificity.

Conclusions: IL-6 level 27 pg/mL or less at the time of admission indicates an infectious etiology while level more than this indicates towards a vasculitic cause.


Biomarkers, C-reactive protein, ESR, Interleukin-6, Infection, Procalcitonin

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de Kruif MD, Limper M, Gerritsen H, Spek CA, Brandjes D, ten Cate H et al. Additional value of procalcitonin for diagnosis of infection in patients with fever at the emergency department. Crit Care Med. 2010 38(2):457-3.

Jones AE, Heffner AC, Horton JM, Marchick MR. Etiology of illness in patients with severe sepsis admitted to the hospital from the emergency department. Clin Infect Dis. 2010;50(6):814-20.

Chakrabartty S, Apong S. Procalcitonin estimation in Kawasaki disease. Indian Pediatr. 2009;46:648.

Harbarth S, Holeckova K, Froidevaux C, Pittet D, Ricou B, Grau GE, et al. Diagnostic value of procalcitonin, interleukin-6, and interleukin-8 in critically ill patients admitted with suspected sepsis. Am J Respir Crit Care Med. 2001;164(3):396-402.

Kollef MH, Sherman G, Ward S, Fraser VJ. Inadequate antimicrobial treatment of infections: a risk factor for hospital mortality among critically ill patients. Chest. 1999;115(2):462-74.

Bilavsky E, Yarden‐Bilavsky H, Ashkenazi S, Amir J. C‐reactive protein as a marker of serious bacterial infections in hospitalized febrile infants. Acta Paediatr. 2009;98(11):1776-80.

Zarkesh M, Sedaghat F, Heidarzadeh A, Tabrizi M, Moghadam KB, Ghesmati S. Diagnostic Value of IL-6, CRP, WBC, and Absolute Neutrophil Count to Predict Serious Bacterial Infection in Febrile Infants. Acta Med Iran. 2015;53(7):408-11.

Andreola B, Bressan S, Callegaro S, Liverani A, Plebani M, Da Dalt L. Procalcitonin and C-Reactive Protein as diagnostic markers of severe bacterial infections in febrile infants and children in the emergency fepartment. Pediatr Infect Dis J. 2007;26(8): 672-7.

Póvoa P. C-reactive protein: a valuable marker of sepsis. Intensive Care Med. 2002;28(3):235-43.

BalcI C, Sungurtekin H, Gürses E, Sungurtekin U, Kaptanoglu B. Usefulness of procalcitonin for diagnosis of sepsis in the intensive care unit. Critical Care 2003;7:85-90.

Delevaux I, Andre M, Colombier M, Albuisson E, Meylheuc F, Bègue RJ, Piette JC, Aumaître O. Can procalcitonin measurement help in differentiating between bacterial infection and other kinds of inflammatory processes?. Ann Rheumat Disa. 2003;62(4):337-40.

Simon L, Gauvin F, Amre DK, Saint-Louis P, Lacroix J. Serum procalcitonin and C-reactive protein levels as markers of bacterial infection: a systematic review and meta-analysis. Clin Infect Dis. 2004; 39(2):206-17.

Uzzan B, Cohen R, Nicolas P, Cucherat M, Perret GY. Procalcitonin as a diagnostic test for sepsis in critically ill adults and after surgery or trauma: a systematic review and meta-analysis. Crit Care Med. 2006; 34(7):1996-2003.

Jones AE, Fiechtl JF, Brown MD, Ballew JJ, Kline JA. Procalcitonin test in the diagnosis of bacteremia: a meta-analysis. Ann Emerg Med. 2007;50(1):34-41.

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(3):210-7.

Kamimura D, Ishihara K, Hirano T. IL-6 signal transduction and its physiological roles: the signal orchestration model. Rev Physiol Biochem Pharmacol. 2003;149:1-38.

Helle M, Brakenhoff JP, Groot ER, Aarden LA. Interleukin 6 is involved in interleukin 1‐induced activities. Eur J Immunol. 1988;18(6):957-9.

Van Snick J. Interleukin-6: an overview. Annu Rev Immunol. 1990;8(1):253-78.

Hou T, Huang D, Zeng R, Ye Z, Zhang Y. Accuracy of serum interleukin (IL)-6 in sepsis diagnosis: a systematic review and meta-analysis. Int J Clin Exp Med. 2015;8(9):15238-45.

Nishimoto N, Kishimoto T. Interleukin 6: from bench to bedside. Nature Rev Rheumatol. 2006;2(11):619-26.

Calandra T, Gerain J, Heumann D, Baumgartner JD, Glanser MP, Swiss-Dutch J5 Study Group. High circulating levels of interleukin-6 in patients with septic shock: Evolution during sepsis, prognostic value and interplay with other cytokines. Am J Med. 1991;91(1):23-9.