Comparison of serum PCT and CRP levels in patients infected by different pathogenic microorganisms: a systematic review and meta-analysis

Abstract

To avoid the abuse and misuse of antibiotics, procalcitonin (PCT) and C-reactive protein (CRP) have been used as new approaches to identify different types of infection. Multiple databases were adopted to search relevant studies, and the articles that satisfied the inclusion criteria were included. Meta-analyses were conducted with Review Manager 5.0, and to estimate the quality of each article, risk of bias was assessed. Eight articles satisfied the inclusion criteria. The concentrations of both PCT and CRP in patients with bacterial infection were higher than those with non-bacterial infection. Both PCT and CRP levels in patients with G− bacterial infection were higher than in those with G+ bacterial infection and fungus infection. In the G+ bacterial infection group, a higher concentration of CRP was observed compared with fungus infection group, while the difference of PCT between G+ bacterial infection and fungus infection was not significant. Our study suggested that both PCT and CRP are helpful to a certain extent in detecting pneumonia caused by different types of infection.

Diagnostic Accuracy of Procalcitonin Compared to C-Reactive Protein and Interleukin 6 in Recognizing Gram-Negative Bloodstream Infection: A Meta-Analytic Study

“…Furthermore, the analyzed covariates were so limited that the difference between specific conditions, including age, background diseases, and PCT test methods, could not be revealed. In the other meta-analysis, Tang et al compared concentrations of PCT in patient with Gramnegative and Gram-positive bloodstream infections; however, the diagnostic indices, such as sensitivity and specificity, were not investigated [12]. The results of this meta-analysis indicated a helpful potential of PCT in recognizing GNBSI with an overall AUC of 0.80.…”

“…In a previous meta-analysis, the mean concentration of PCT was found to be around 6 ng/mL in patients with Gram-positive and/or fungal infections, which is significantly higher than in healthy controls [12]. However, in Gram-negative infections, the PCT level was found to be even higher with its value being around 13 ng/mL, which indicates the level of induced PCT concentration differs among pathogens even in bacteremia [12]. Though the proposed optimal cutoffs varied greatly from 0.291 ng/mL to 16.9 ng/mL in our included studies, the results consistently indicated a higher level of PCT in Gram-negative infections than in Gram-positive and/or fungal infections [17-20, 22, 23, 26-28, 30, 31, 34, 40, 41].…”

“…Though the value of PCT in recognizing GNBSI has been explored, utility of the results in most studies is hampered by either small sample size or limited clinical information. Only two meta-analyses were published on this topic [12,13]. He et al estimated the overall accuracy of PCT for diagnosing GNBSI and found its sensitivity being 0.73 (95% CI 0.68 to 0.78), specificity being 0.74 (95% CI 0.64 to 0.81), DOR being 7.59 (95% CI 5.31 to 10.85), and AUC being 0.79 [13].…”

“…In healthy individuals, PCT found in the circulation would be ≤0.1 ng/mL [50]. Normal or slightly elevated PCT level in critically ill septic patients was more likely to be a result of viral infection or systemic inflammatory response of noninfectious origin rather than bacteremia (including both Gram-negative and Gram-positive infection) or fungemia [12,22,48,51]. In a previous meta-analysis, the mean concentration of PCT was found to be around 6 ng/mL in patients with Gram-positive and/or fungal infections, which is significantly higher than in healthy controls [12].…”

“…So far, the value of PCT in early identification of GNBSI is still argued by researchers and is poorly explored in guidelines [11]. Two meta-analyses on this topic were published before, but their clinical utility was limited by either poor investigation of underlying heterogeneity or not investigating the proper diagnostic indices [12,13]. Therefore, we herein systematically assessed the diagnostic accuracy of PCT in recognizing GNBSI in patients with suspected BSI and examined the factors associated with threshold and diagnostic accuracy.…”