Procalcitonin to guide taking blood cultures in the intensive care unit; a cluster-randomized controlled trial.

OBJECTIVES: We aimed to study the safety and efficacy of procalcitonin in guiding blood cultures taking in critically ill patients with suspected infection. METHODS: We performed a cluster-randomized, multi-centre, single-blinded, cross-over trial. Patients suspected of infection in whom taking blood for culture was indicated were included. The participating intensive care units were stratified and randomized by treatment regimen into a control group and a procalcitonin-guided group. All patients included in this trial followed the regimen that was allocated to the intensive care unit for that period. In both groups, blood was drawn at the same moment for a procalcitonin measurement and blood cultures. In the procalcitonin-guided group, blood cultures were sent to the department of medical microbiology when the procalcitonin was >0.25 ng/mL. The main outcome was safety, expressed as mortality at day 28 and day 90. RESULTS: The control group included 288 patients and the procalcitonin-guided group included 276 patients. The 28- and 90-day mortality rates in the procalcitonin-guided group were 29% (80/276) and 38% (105/276), respectively. The mortality rates in the control group were 32% (92/288) at day 28 and 40% (115/288) at day 90. The intention-to-treat analysis showed hazard ratios of 0.85 (95% CI 0.62-1.17) and 0.89 (95% CI 0.67-1.17) for 28-day and 90-day mortality, respectively. The results were deemed non-inferior because the upper limit of the 95% CI was below the margin of 1.20. CONCLUSION: Applying procalcitonin to guide blood cultures in critically ill patients with suspected infection seems to be safe, but the benefits may be limited. TRIAL REGISTRATION: ClinicalTrials.gov identifier: ID NCT01847079. Registered on 24 April 2013, retrospectively registered.

The diagnostic accuracy of procalcitonin for bacteraemia: a systematic review and meta-analysis.

The diagnostic use of procalcitonin for bacterial infections remains a matter of debate. Most studies have used ambiguous outcome measures such as sepsis instead of infection. We performed a systematic review and meta-analysis to investigate the diagnostic accuracy of procalcitonin for bacteraemia, a proven bloodstream infection. We searched all major databases from inception to June 2014 for original, English language, research articles that studied the diagnostic accuracy between procalcitonin and positive blood cultures in adult patients. We calculated the area under the summary receiver-operating characteristic (SROC) curves and pooled sensitivities and specificities. To minimize potential heterogeneity we performed subgroup analyses. In total, 58 of 1567 eligible studies were included in the meta-analysis and provided a total of 16,514 patients, of whom 3420 suffered from bacteraemia. In the overall analysis the area under the SROC curve was 0.79. The optimal and most widely used procalcitonin cut-off value was 0.5 ng/mL with a corresponding sensitivity of 76% and specificity of 69%. In subgroup analyses the lowest area under the SROC curve was found in immunocompromised/neutropenic patients (0.71), the highest area under the SROC curve was found in intensive-care patients (0.88), sensitivities ranging from 66 to 89% and specificities from 55 78%. In spite of study heterogeneity, procalcitonin had a fair diagnostic accuracy for bacteraemia in adult patients suspected of infection or sepsis. In particular low procalcitonin levels can be used to rule out the presence of bacteraemia. Further research is needed on the safety and efficacy of procalcitonin as a single diagnostic tool to avoid taking blood cultures.