Can procalcitonin be used to diagnose Gram-negative bloodstream infection? Evidence based on a meta-analysis

Procalcitonin (PCT) is a useful biomarker for systemic bacterial infection, and many studies have described the correlation between high serum PCT level and Gram-negative bloodstream infection (BSI), whereas the diagnostic accuracy of PCT for this kind of episode has not been summarized. This study aimed to estimate the overall accuracy of serum PCT for diagnosing Gram-negative BSI through a meta-analysis.

We searched PubMed, EMBASE, Web of Science, and Scopus database for studies that met the inclusion criteria. The pooled sensitivity, specificity, positive/negative likelihood ratio (PLR/NLR), and diagnostic odds ratio (DOR) were calculated using bivariate random-effects models. Summary receiver operating characteristic (SROC) curve and area under the curve (AUC) were used to summarize overall diagnostic accuracy.

Our meta-analysis included 13 studies involving 4,513 subjects. Summary estimates for PCT in diagnosing Gram-negative BSI were as follows: sensitivity, 0.73 (95% CI 0.68 to 0.78); specificity, 0.74 (95% CI 0.64 to 0.81); PLR, 2.77 (95% CI 2.07 to 3.70); NLR, 0.37 (95% CI 0.31 to 0.42); DOR, 7.59 (95% CI 5.31 to 10.85); AUC, 0.79 (95% CI 0.75 to 0.82). The corresponding summary performance estimates for using PCT in differentiating Gram-negative BSI from gram-positive BSI were as follows: sensitivity, 0.73 (95% CI 0.66 to 0.78); specificity, 0.70 (95% CI 0.59 to 0.78); PLR, 2.40 (95% CI, 1.83 to 3.15); NLR, 0.39 (95% CI 0.33 to 0.46); DOR, 6.15 (95% CI 4.40 to 8.60); AUC, 0.77 (95% CI 0.73 to 0.81).

PCT may have a limited diagnostic value for Gram-negative BSI.