Diagnostic Value of Procalcitonin, Interleukin-6, and Interleukin-8 in Critically Ill Patients Admitted with Suspected Sepsis

Abstract

To assess the diagnostic value of procalcitonin (PCT), interleukin (IL)-6, IL-8, and standard measurements in identifying critically ill patients with sepsis, we performed prospective measurements in 78 consecutive patients admitted with acute systemic inflammatory response syndrome (SIRS) and suspected infection. We estimated the relevance of the different parameters by using multivariable regression modeling, likelihood-ratio tests, and area under the receiver operating characteristic curves (AUC). The final diagnosis was SIRS in 18 patients, sepsis in 14, severe sepsis in 21, and septic shock in 25. PCT yielded the highest discriminative value, with an AUC of 0.92 (CI, 0.85 to 1.0), followed by IL-6 (0.75; CI, 0.63 to 0.87), and IL-8 (0.71; CI, 0.59 to 0.83; p < 0.001). At a cutoff of 1.1 ng/ml, PCT yielded a sensitivity of 97% and a specificity of 78% to differentiate patients with SIRS from those with sepsis-related conditions. Median PCT concentrations on admission (ng/ ml, range) were 0.6 (0 to 5.3) for SIRS; 3.5 (0.4 to 6.7) for sepsis; 6.2 (2.2 to 85) for severe sepsis; and 21.3 (1.2 to 654) for septic shock (p < 0.001). The addition of PCT to a model based solely on standard indicators improved the predictive power of detecting sepsis (likelihood ratio test; p = 0.001) and increased the AUC value for the routine value-based model from 0.77 (CI, 0.64 to 0.89) to 0.94 (CI, 0.89 to 0.99; p = 0.002). In contrast, no additive effect was seen for IL-6 (p = 0.56) or IL-8 (p = 0.14). Elevated PCT concentrations appear to be a promising indicator of sepsis in newly admitted, critically ill patients capable of complementing clinical signs and routine laboratory parameters suggestive of severe infection.

Evaluation of C-reactive protein, procalcitonin, tumor necrosis factor alpha, interleukin-6, and interleukin-8 as diagnostic parameters in sepsis-related fatalities

“…A total of 18 cases (eight sepsis-related fatalities and ten control cases) were included in this study. According to our observations, serum CRP and procalcitonin concentrations were significantly different between sepsis cases and control subjects, whereas serum TNF-α, IL-6, and IL-8 values were not significantly [2]. Multiple organ failure of various noninfectious causes (trauma, burn, myocardial infarction, pancreatitis) is well known to induce a rise in inflammatory cytokine levels.…”

“…Thus, there is an unmet need for clinical or laboratory tools distinguishing between the systemic inflammatory response syndrome and the various forms of sepsis [2].…”

“…Among the potentially useful sepsis markers, tumor necrosis factor alpha (TNF-α), interleukin 2 (IL-2), interleukin 6 (IL-6), interleukin 8 (IL-8), and interleukin-10 (IL-10) have been proposed to be the most promising candidates [1,2,9].…”

“…They found that procalcitonin was the best indicator of infection in newly admitted critically ill patients, whereas measurement of IL-6 and IL-8 was nonoptimal for discriminating patients with infectious from those with noninfectious diseases [2].…”

Spielen CRP-Spiegel neben IL-6 und PCT noch eine Rolle für Patienten auf Intensivstationen?/Are circulating levels of CRP compared to IL-6 and PCT still relevant in intensive care unit patients?

“…sowohl mit dem Schweregrad der Erkrankung als auch mit der nachfolgenden Mortalit ä t korrelieren [8,9,25,26] . In einer Studie an 472 kritisch kranken Intensivpatienten konnten Jensen et al [51] zeigen, dass hohe PCT-Werte und ein PCT-Anstieg von einem Tag fr ü he Indikatoren f ü r Mortalit ä t innerhalb 90 Tage nach Aufnahme auf der Intensivstation waren.…”