Korean J Lab Med.  2010 Apr;30(2):153-159. 10.3343/kjlm.2010.30.2.153.

Evaluation of the Clinical Performance of an Automated Procalcitonin Assay for the Quantitative Detection of Bloodstream Infection

• Kim KE
• Han JY

• KMID: 1096801
• DOI: http://doi.org/10.3343/kjlm.2010.30.2.153

Abstract

BACKGROUND
Bloodstream infection (BSI) is associated with a high mortality rate. Since the origin of infection is demonstrated in approximately 2/3rds of cases, early and established biomarkers are warranted. We evaluated the clinical performances of automated procalcitonin (PCT) and C-reactive protein (CRP) assays for the quantitative detection of BSI. Analytical performance of the VIDAS(R) B.R.A.H.M.S PCT assay (bioMerieux, France) was assessed and also compared with the semi-quantitative PCT-Q test (B.R.A.H.M.S Aktiengesellschaft, Germany).
METHODS
We prospectively included consecutive patients divided into 3 groups at the Dong-A University Medical Center. Patients were categorized according to the criteria of the American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference (ACCP/SCCM), and also on the basis of catheter-associated bacteremia.
RESULTS
A total 77 patients were enrolled. All mean values of PCT and PCT-Q were consistent with the reference value. Measured PCT concentrations showed good linearity (r=0.983). The between-run, within-run, and total imprecisions were below 5%. The PCT levels in gram-negative bacteremia were significantly higher than those in gram-positive bacteremia. Furthermore, the PCT concentrations were significantly different among non-infection, bacteremia, sepsis, severe sepsis, and septic shock groups. Our study showed that PCT >0.3 ng/mL had 95.0% sensitivity and 97.3% specificity, whereas CRP >5.46 mg/dL had 85.0% sensitivity and 86.5% specificity for diagnosing sepsis.
CONCLUSIONS
We suggest that, compared with CRP, PCT is a better diagnostic and discriminative biomarker of sepsis categorized according to the ACCP/SCCM. Moreover, catheter-associated bacteremia could be discriminated from sepsis using PCT concentration.

Keyword

Procalcitonin; C-reactive protein; Sepsis; Bacteremia

MeSH Terms

Adult
Bacteremia/*diagnosis
Biological Markers/analysis/blood
C-Reactive Protein/analysis
Calcitonin/*blood
Female
Humans
Male
Middle Aged
Protein Precursors/*blood
ROC Curve
Sensitivity and Specificity
Sepsis/diagnosis

Figure

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  Fig. 1. Flow diagram of the subjects included in this study. Abbreviations: B/C, blood culture; ER, emergency room; SIRS, systemic inflammatory response syndrome.

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  Fig. 2. Linearity of concentration in the PCT test. Abbreviation: PCT, procalcitonin.

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  Fig. 3. Serum PCT level (A) and CRP level (B) in patients with no infection, bacteremia (catheter associated), sepsis, severe sepsis, and septic shock. Data are presented as box plots with median lines, 25- and 75-percentile boxes, and 10- and 90-percentile error bars. A log scale is used for the Y-axis in (A). Abbreviations: PCT, procalcitonin; CRP, C-reactive protein.

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  Fig. 4. The ROC curves of PCT (AUC, 0.982) and CRP (AUC, 0.871) for the diagnosis of sepsis. Abbreviations: PCT, procalcitonin; CRP, C-reactive protein; AUC, area under the curve.

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