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Open Access Research article

A composite score combining procalcitonin, C-reactive protein and temperature has a high positive predictive value for the diagnosis of intensive care-acquired infections

Laurent Robriquet14*, Caroline Séjourné1, Eric Kipnis2, Michele D’herbomez3 and François Fourrier1

Author affiliations

1 Service de Réanimation Polyvalente, Centre Hospitalier Universitaire de Lille, 59000 Lille, France

2 Service de Réanimation Chirurgicale, Centre Hospitalier Universitaire de Lille, 59000 Lille, France

3 Service de Médecine Nucléaire, Centre Hospitalier Universitaire de Lille, 59000 Lille, France

4 Service de Réanimation Polyvalente, Hôpital Roger Salengro - Centre Hospitalier Universitaire de Lille, Rue Emile Laine, 59037 Lille, Cedex France

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Citation and License

BMC Infectious Diseases 2013, 13:159  doi:10.1186/1471-2334-13-159

Published: 2 April 2013

Abstract

Background

Nosocomial infection diagnosis in the intensive care unit (ICU) remains a challenge. We compared routine measurements of procalcitonin (PCT), C-reactive protein (CRP), white blood cell count (WBC) and temperature in the detection of ICU-acquired infections.

Method

Prospective observational cohort study in a University hospital Medicosurgical ICU. All patients admitted to the ICU ≥ 5 days (n = 141) were included into two groups, either infected (documented infection, n = 25) or non-infected (discharged from the ICU without diagnosis of infection, n = 88).

Results

PCT, CRP, WBC and temperature progression from day −4 (D-4) to day 0 (D0) (day of infection diagnosis or ICU discharge) was analysed. Differences (Δ) were calculated as D0 levels minus the lowest preceding value. D0 PCT and CRP were significantly increased in infected compared to non-infected patients (median, 1st and 3rd quartiles): 3.6 ng/mL (0.92-25) for PCT, 173 mg/L (126–188) for CRP versus 0.02 ng/mL (0.1-0.9) and 57 mg/mL (31–105) respectively (p < 0.0001). In multivariate analysis, D0 temperature > 38.6°C, PCT > 1.86 ng/mL, and CRP > 88 mg/L, performed well (AUCs of 0.88, 0.84, and 0.88 respectively). The sensitivity/specificity profiles of each marker (76%/94% for temperature, 68%/91% for PCT, and 92%/70% for CRP) led to a composite score (0.068 × D0 PCT + 0.005 × D0 CRP + 0.7 × temperature) more highly specific than each component (AUC of 0.90 and sensitivity/specificity of 80%/97%).

Conclusion

Combining CRP, PCT and temperature is an approach which may increase of nosocomial infection detection in the ICU.

Keywords:
Nosocomial infection; Procalcitonin; C-reactive protein; Intensive care unit