Elecsys^® IL-6

Clinical signs suggestive of sepsis are non-specific, making diagnosis of sepsis difficult.⁵ Blood cultures remain the gold standard for diagnosis of patients with suspected sepsis, however, they have several limitations.^{6, 7}

Limitations of blood cultures in sepsis diagnosis:^{6, 7}

• Require up to 5 days to obtain the results
• Lack sensitivity
• Easy to contaminate
• Cannot assist on early sepsis management decisions

Timely diagnosis and initiation of effective antibiotic treatment and sepsis management has been shown to improve patient outcomes. Almost 80% of patients with severe sepsis survive if treatment is initiated within 1 hour of diagnosis. Survival declines rapidly if treatment is delayed further, dropping to only 42% if initiated 6 hours after diagnosis.⁸ In addition, it is desirable to prevent unnecessary antibiotic usage in order to reduce treatment costs, reduce the risk of adverse reactions and to slow down the spread of antibiotic-resistant bacteria.^{9, 10}

There is considerable unmet medical need in sepsis, and biomarkers may have an important clinical role to play. Biomarkers can indicate the presence of sepsis, differentiate bacterial from viral or fungal infection, differentiate local from systemic infection, stratify severity of sepsis, may help to guide antibiotic therapy, provide prognostic information, evaluate response to therapy, predict septic complications and predict the development of organ dysfunction. However, the exact role of biomarkers is yet to be defined.⁵

Unmet medical needs in the management of sepsis and suspected sepsis:

• Diagnosis and differential diagnosis of infection⁵
• Recognition and stratification of severity of sepsis⁵
• Early and appropriate decision regarding antibiotic therapy decisions^{9, 11}

Interleukin-6 (IL-6) is an early marker for inflammation in sepsis

Il-6, a key mediator for inflammation and an early alarm signal of infection that becomes elevated as part of the inflammatory response, has emerged as a valuable biomarker in the management of sepsis.¹²

IL-6 levels predict development of septic complications

In a study of 1,032 patients with severe trauma, patients who subsequently developed septic complications had the highest IL-6 levels on day 1 following injury.¹⁴ Similarly, in a study of 50 patients following major surgery, IL-6 levels were correlated with the development of septic complications during the first 5 days following surgery (area under the curve [AUC] 0.82; 95% CI: 0.66 – 0.98), with a sensitivity of 90% and a selectivity of 58%. Furthermore, when IL-6 levels and clinical indicators were combined, sensitivity and selectivity increased to 100% and 79%, respectively.¹⁵

Early peak IL-6 levels correlate significantly with the development of SIRS and sepsis. The degree of elevation inIL-6 levels can be used to differentiate SIRS from severe sepsis anf septic shock, with higher IL-6 levels correlating with increased severity.¹⁶ 

As a marker for systemic inflammation, high IL-6 levels may be predictive of future organ dysfunction.¹² In addition, continually elevated IL-6 levels have been reported to be predictive of mortality in patients with sepsis. ¹⁶

Benefits

• Aid in the management of critically ill patients
• Optimized laboratory workflow
• Available on a fully automated platform
• Small sample volume